Here’s one small example. At the Los Angeles Zoo, I recently participated in a study with on the effects of environmental enrichment on meerkat behavior. Thoughtfully designed environmental enrichment programs, it is thought, allow captive animals to display a wider variety of naturalistic behaviors. A wealth of evidence suggests that when animals exhibit their natural behaviors, zoo visitors have a better and more educational experience, and animal welfare is increased. Unfortunately, one side effect of captivity is the possible emergence of non-naturalistic repetitive or stereotypic behaviors.

Stereotypic behaviors vary according to the species, but might include swaying, coprophagy, regurgitation and reingestion, or pacing. When combined with stereotypic swimming patterns, pacing may actually be the most common form of stereotypy across species in modern zoos. While these behaviors may in fact be more stressful for zoo visitors than for the animals themselves, zoos still have a responsibility to minimize them as much as possible. Other stereotypies may feature or result in various forms of self-harm, which are of course more dangerous. Birds pluck their feathers, horses nip at their flanks, canids, felids, and bears over-groom themselves, turtles may bite their legs, and snakes may chew on their tails.

Enrichment might serve to reduce the occurrence of these and other compulsive behaviors. Legally, environmental enrichment is only required for non-human primates and for domestic dogs. However, many zoos strive to enrich the lives of all the animals in their care, where appropriate.

Until recently, the meerkat enclosure at the LA Zoo was not provisioned with any specific form of environmental enrichment, due to a belief among the keepers that it would increase aggression between the meerkats. (The meerkats are housed socially, however; the presence of social partners may itself be one of the most effective forms of enrichment.)

The pilot experiment that we conducted indicated that, contrary to expectations, adding environmental enrichment (in the form of perforated, hollow balls filled with mealworms) to the enclosure did not modify the meerkats’ daily activity cycles. However, it did affect social behavior. The meerkats exhibited more affiliative behaviors (especially allogrooming), while there were no differences in submissive or aggressive behaviors, compared with a baseline.

While a full experiment should still be conducted, this is but one example of empirical science providing important information in order to help zoo keepers and curators provide the most healthy, stimulating environment possible for their non-human charges.

The Empirical Zoo
In addition to the need for improving the care of animals resident in a zoo, there are at least three broader reasons that empirical science ought to be conducted in zoos.

First, in situ conservation efforts can be more explicitly targeted and better designed if they are informed by empirical knowledge derived from scientific observations of the habits and behaviors of the target species. Likewise, captive breeding paradigms are more successful when governed by knowledge of natural mating and parenting behaviors. The release programs that follow captive breeding are likewise more predictable when based upon knowledge of natural feeding, spatial navigation, and social behaviors.

Second, zoo animals provide a means of developing models for disorders of behavior and cognition. The growing awareness of psychopathology in animals among veterinarians, zoo keepers and curators, and other animal welfare professionals has led to an increased ability to identify phenotypic markers of mental distress – that is, overt behavioral indicators – in non-human species. This represents a novel approach towards uncovering both proximate and ultimate explanations for mental disorders, as well as means for intervention. Indeed, while critical for research and conservation efforts, the modern zoo can be, in a way, a living laboratory for psychopathology, and considering zoo animals as model species would represent a new kind of translational model in psychiatry.

Finally, zoo populations provide a more naturalistic source of non-human animals for investigating behavior and cognition compared with laboratory studies. An empirical zoo ought to be crawling with graduate students, post-docs, and other researchers doing basic science. (One research poster I saw at last year’s Association of Zoos and Aquariums meeting suggested that visitors also learned more while watching a research demonstration, compared with a more traditional keeper talk!)

Each of these types of research conducted in modern, ethical zoos serves the scientific endeavour, contributes towards the development of more effective conservation practices, and generates knowledge towards the improvement of ethical management practices for captive animals.

The Human Animal
The human animal is a species that is often overlooked when it comes to bringing an empirical approach to zoo operations. Millions of dollars are spent each year at zoos in an effort to increase visitor numbers, to improve the educational experience, to expand membership, and to seek out new sources of funding.

A scientific approach can also inform the way in which zoos engage their human visitors. Zoos make claims about the importance of living animals for teaching people of all ages about conservation. Zoo animals are often referred to as “ambassadors” for their wild counterparts.

Does the presence of live animals at a zoo result in better learning outcomes compared with the stuffed animals at a natural history museum or filmed animals on a movie screen? What is the role of educators and of educational content in driving conservation behavior? Are the educational programs at a given zoo effective at promoting conservation attitudes? Zoo professionals have long made claims about the positive effects of zoos for human visitors; it is critical to use the tools of empirical science to evaluate those claims. (And, if the answer is no, then zoos are in a position to ask how to improve the educational program such that the answer becomes yes!)

And the best part? Much of this research can be conducted fairly cheaply: all you really need is a stopwatch, a pair of binoculars, a few video cameras, some clipboards, and lots of time and patience.

If an intelligent alien species landed on the small bit of galactic rock that we call home, they might get out of their spaceships, have a look around, and decide that we—that is, our species—are the master builders on our planet. There would be plenty of reasons to think so. We build bridges spanning enormous waterways, aptly named skyscrapers, and stadiums that seat tens of thousands. And that doesn’t even scratch the surface of the diversity of structures we build: schools, airports, apartment buildings, shopping malls, a Starbucks on every corner.

But we’re not the only species that modifies the environment to suit its needs. Some animals simply set up shop in pre-existing spaces, like bears that spend the winter hibernating in natural caves. Some can build a home by simply moving around an impressive amount of dirt, like gophers and ants. Some animals, however, create more elaborate spaces, transforming their environment in the process. If a group of aliens did land on our planet, they would just have to look a bit harder to see it.

Read the rest of my latest piece over at Nautilus Magazine: You Didn’t Build That: The Best Animal Engineers

Image via Flickr/Minette Layne.

From time to time, politicians and other rulers-of-men like to categorize the natural world not according to biology, but rather for convenience or monetary gain. Take, for example, the tomato. The progenitor of ketchup is a seed-bearing structure that grows from the flowering part of a plant. It is, by definition, a fruit. In 1893, however, the US Supreme Court ruled in the case of Nix v. Hedden that the tomato was a vegetable, subject to vegetable import tariffs. Even if the tomato is, technically, a fruit, it tends to be treated in American cuisine as a vegetable, wantonly littering our salads with its jelloey gooeyness.

Corn and rice are another good example. The Bible forbids Jewish people from eating chametz – foods made from wheat, barley, spelt, rye, or oats – on Passover. Ashkenazi Jews consider corn, rice, and legumes, a class of foods called kitniyot, as forbidden on Passover as well. It isn’t that they’re forbidden, per se, but that they’re easily confused for the real thing. As I learned in my high school Talmud class, the medieval Rabbis decided to forbid these not-technically-forbidden grains because of a principle called marit ayin, which literally means “what it looks like.” The Wikipedia explanation is quite good: “While not against the laws of passover to consume kitniyot, a person might be observed eating them and thought to be eating chametz despite the law, or erroneously conclude that chametz was permitted. To avoid this confusion, they were simply banned outright.”

Still, neither the Supreme Court’s reclassification of the tomato is a fruit, nor the medieval Rabbis’ designation of corn and rice as forbidden grains, is the most amusing example of non-scientific categorization. The Catholic Church has them all beat.

There were once between 60 and 400 million beavers (Castor canadensis) occupying the rivers and streams of North America, from the great white north to the deserts of northern Mexico. Then the Europeans came. With them came disease along with an insatiable desire for beaver pelts and for beaver castoreum, a urine-like secretion often used in perfume and cologne. Combined with the once-sustainable hunting of beaver by indigenous North Americans for their meat, the beaver population rapidly declined. (The species is now rebounding, thanks to trapping regulations, and now includes some 6 to 12 million individuals)

In addition to disease, the European settlers also brought Catholicism with them, and successfully converted a large proportion of the indigenous population. And the native Americans and Canadians loved their beaver meat.

So in the 17th century, the Bishop of Quebec approached his superiors in the Church and asked whether his flock would be permitted to eat beaver meat on Fridays during Lent, despite the fact that meat-eating was forbidden. Since the semi-aquatic rodent was a skilled swimmer, the Church declared that the beaver was a fish. Being a fish, beaver barbeques were permitted throughout Lent. Problem solved!

The Church, by the way, also classified another semi-aquatic rodent, the capybara, as a fish for dietary purposes. The critter, the largest rodent in the world, is commonly eaten during Lent in Venezuela. “It’s delicious,” one restaurant owner told the New York Sun in 2005. “I know it’s a rat, but it tastes really good.”

And it’s not just oversized rats that make for good eating in the run up to Easter, either. I have it on authority from my cousin Jerome (who knows everything) that “iguana tail soup is a fave for Lenten meals in Nicaragua.” Yum.

For more on beavers:
Respect the Boundary of the Beaver

For more on bad taxonomy:
Are Sheep Better at Botany than the US Government?

For more on dietary traditions during Lent:
Hyenas Give Up Eating Garbage For Lent, Hunt Donkeys Instead

Naiman R.J., Johnston C.A. & Kelley J.C. (1988). Alteration of North American Streams by Beaver, BioScience, 38 (11) 753-762. DOI: 10.2307/1310784

Worsley P. (2009). The Physical Geology of Beavers, MERCIAN GEOLOGIST, 17 (2) 112-121. DOI:

Image via Flickr/Minette Layne.

There is a rich tradition in psychology and neuroscience of using animals as models for understanding humans. Humans, after all, are enormously complicated creatures to begin even from a strictly biological perspective. Tacking on the messiness that comes with culture makes the study of the human mind tricky, at best. So, just as biomedical scientists have relied upon the humble mouse, psychological and cognitive scientists have too turned to our evolutionary cousins in the animal kingdom as a means of better understanding ourselves.

In her new book Animal Wise, journalist Virginia Morrell recounts a conversation with one researcher who pointed out that decades of research were built upon “rats, pigeons, and college sophomores, preferably male.” The college undergrads stood in for all of humanity, the rats served as representatives of all other mammals, and pigeons served as a model for the rest of the animal kingdom.

The silly part isn’t that non-human animals can be used effectively as a means of understanding more about our own species. The idea is simple: understand how a simple system works, and you can make careful inferences about the way that complex systems work. That is (or should be) obvious. In his interview with CNN today, memory research pioneer and Nobel Prize winner Eric Kandel said as much: “Rather than studying the most complex form of memory in a very complicated animal, we had to take the most simple form — an implicit form of memory — in a very simple animal.”

The silly part is that scientists for so long confined themselves to such a limited sample of the diversity offered by the animal kingdom. And this is where the brilliance of Kandel’s approach is particularly manifest. He continued, “So I began to look around for very simple animals. And I focused in on the marine snail Aplysia.”

Kandel wasn’t the only researcher to change the course of scientific discovery by introducing a new model species to his field. Sydney Brenner, who popularized the use of the nematode worm C. elegans, said (quoted by Kandel),

What you need to do is to find which is the best system to experimentally solve the problem, and as long as it [the problem] is general enough you will find the solution there.

The choice of an experimental object remains one of the most important things to do in biology and is, I think, one of the great ways to do innovative work… The diversity in the living world is so large, and since everything is connected in some way, let’s find the best one.

The idea is simple: choose the species best able to help you answer the scientific questions you wish to ask. If that’s a rat or a pigeon, then use the rat or the pigeon. But chances are there’s a species even more uniquely suited. In graduate school, I studied the chicken as a means of understanding development of social cognition. More specifically, I wanted to understand the starting state of the mind, and then understand how different experiences shaped the mind in different ways.

Why not use human infants?

For one thing, only a few data points can typically be collected from any individual infant in a typical experiment of infant cognition. This is partly due to the limited attention span of a young infant, and partly due to the fact that infants frequently fall asleep, or become fussy. This, however, is simply a logistical concern. More important is that infants begin learning quite a bit about their environment soon after they’re born. One researcher found that by two months, a typical human infant has accumulated at least two hundred hours of visual experience, comprised of as many as 2.5 million eye movements. So by the time infants are old enough to participate in experiments, they’ve had a massive amount of experience. Thus, even if you could ethically raise a human infant in a completely controlled environment, infants are still essentially tiny little learning machines. And that’s a problem if you want to understand the starting state of the mind. It would be like studying a salad to figure out how plants grow.

There’s more. Humans are an altricial species, which means that they’re born helpless. They can’t see very well. They’re completely uncoordinated. They can’t move around on their own. They can’t find their own food. They don’t even have the muscles required to hold their massive heads up above their necks. Thus, human infants require years worth of parental care. Mom and Dad are really important, if you’re a human.

This doesn’t just mean that infants need to be at least a few months old to participate in an experiment. It also means that while they could be mentally proficient at a given skill, they could be unable to adequately demonstrate that proficiency. As developmental psychologists say, there could be a contradiction between competence and performance. For example, human infants aren’t able to control their reaching actions for several months after birth. If your experiment relies on reaching behavior (or on motor coordination more generally), then it would fail to uncover nuances in infants’ cognitive abilities for whom the experimental requirements are simply too difficult. It was once thought that newborn infants weren’t able to visually track objects that moved in front of them. Researchers later discovered that infants are quite good at object tracking when they are presented with stroboscopic, rather than continuous, motion. Babies would fare quite well tracking people in a night club. Given these sorts of contradictions, it can be difficult to interpret task-related failure: an infant could fail at a task because they truly lack the cognitive abilities necessary to succeed, or it could simply be that the task is not optimized for their immature perceptual or motor abilities.

Controlled rearing studies with non-human animals solve these problems. In particular, conducting a controlled rearing study with a precocial species – that is, a species that is able to survive on its own following birth and therefore needs no parental care – solves these problems.

Kandel chose the sea slug because its nervous system consists of just twenty thousand neurons, some of which are even visible to the naked eye. Despite the tremendous gulf separating humans from sea slugs, the latter have proven remarkably useful as a model species, and have allowed researchers the ability to uncover the basic molecular underpinnings of human learning and memory.

While undoubtedly more complex than the California sea slug, the domestic chicken is uniquely suited to controlled rearing studies of cognition. Chickens are extremely precocial, allowing them to survive without parental care immediately upon hatching. Unlike human infants, chickens are born with good visual acuity and depth perception. While human infants don’t pass the famous visual cliff test until well after a year, chickens pass the test on the first day of life.

Despite differences in macroarchitecture, the circuitry of the avian and mammalian brains (here: the auditory cortex) is very similar.

The chicken brain, like the nervous system of the sea slug, is ask in many ways comparable to the human brain. Despite the fact that the mammalian brain is organized into layers while the avian brain is organized in clusters of cells called nuclei, the microstructure – that is, the circuitry – remains quite similar in some ways.

Indeed, ethologists have used the domestic chicken to investigate behavior for at least one hundred and fifty years, with psychologists and cognitive scientists joining them more recently. Chickens have been used to probe the development of object representation, numerical cognition, biological motion perception, geometric reorientation, spatial navigation, and face perception.

There’s one last benefit that comes with the use of chickens in cognition research, which is that they imprint. Like some other birds, infant chickens imprint onto the first moving object that they see, treating it as a source of emotional comfort. Under normal circumstances, these birds imprint to the mother hen. However, they will also imprint onto just about anything else that moves on its own. Even an animated object on a computer screen! Konrad Lorenz, the father of ethology, famously imprinted young goslings to his boots.

A typical study with animals like rats or mice requires that a researcher spend hours (or days) training his or her animals to perform some task or to discriminate between stimuli. The imprinting instinct allows researchers to test chickens without training. How does this work? When separated, chickens really want to reunite with their imprinted object by reducing the physical separation between the two. That is, if you move the imprinted object away, and then let the chicken free, it will run right up to “mom.” If you give chickens a choice between approaching two different objects, they’ll approach the one that they perceive as more similar to the one to which they imprinted.

Say you imprint a chicken to a red ball. Then, you give it the choice between approaching a red ball and a red cube. If they are more likely to approach the red ball, then you can reasonably infer that chickens can perceive the difference between a ball and a cube. If, however, their approach is the result of random chance (they only approach the ball 50% of the time), then they probably don’t notice the objects’ shapes.

The filial imprinting instinct therefore provides a biologically valid way of investigating cognitive abilities without requiring a training program.

Will the chicken be, for developmental psychology, what the sea slug Aplysia has been for learning and memory?

For more on chicken cognition:
Day Old Chickens Prefer The Same Music You Do
If Chickens Like Consonant Music, Will They Hate B.B. King? That’s Not Even the Right Question to Ask

Header photo via Flickr/cskk.

Original image by Charles M. Schulz/Peanuts.

Like this San Diego Zoo polar bear, I intend to hibernate through the weekend. And then, we prepare the defense.

Image: Polar Bear at the San Diego Zoo, copyright the author.

Peter Cook with Ronan

Jason titled his post on The Thoughtful Animal two weeks ago: Ronan the Sea Lion Dances To The Backstreet Boys. So What? He then did an excellent job of answering the title’s question: Ronan, as a sea lion, is vocally inflexible, so her beat-keeping ability represents a challenge to an influential theory suggesting vocal flexibility (and mimicry, specifically) is a prerequisite for synchronizing movement to rhythmic sounds. This has potentially broad implications, including the possibility that human dance, a phenomenon once thought by many psychologists to be truly unique, may be rooted in general brain mechanisms shared across a wide range of species.

I’m the first author on the paper about Ronan, and following an email exchange last week, Jason was kind enough to offer me the chance to write a guest post. I wanted to address one issue in particular, one that is likely to be a focus in ongoing comparative research into rhythm: spontaneity.

As was noted, Ronan did not show spontaneous beat keeping ability. That is, when we first exposed her to rhythmic sounds, she did not move in time. She did, following training at two set rates, or tempos, spontaneously find and keep the beat across a wide range of novel tempos, even when we manipulated the speed of actual music. But before showing this general capability for beat keeping, we had to give her explicit training.

Ronan’s training is potentially important to the debate because many people (including many psychologists) believe that humans do NOT need to be trained to find and match the rhythm in music. Rather, it seems to come naturally to us. Jason echoed this belief in his original post when he noted that one response to our findings might be this:

Perhaps any animal with sufficient training can learn rhythmic entrainment. While damaging to the vocal learning hypothesis, it would just shift the goalposts slightly – what is it about humans, songbirds, parrots, and the rest that allows them to do this so easily and so flexibly, without extensive training?

Following our findings with Ronan (and the concurrent findings of rhythmic sensitivity in a chimpanzee), I believe many will be interested in further exploring the role of vocal mimicry in spontaneous (if not trained) beat keeping. This is well and good, and emblematic of healthy science, in which new data beget new theories to be tested. However, this work should be grounded in a valid representation of the existent human data, and it turns out these data are very equivocal when it comes to spontaneity of beat keeping! This may be surprising — I recognize that, to most adults, beat keeping feels spontaneous, effortless, and sometimes obligatory (e.g., try not walking in time to the beat of street musicians when you pass them). However, it is all too easy to disregard the very long history with music and rhythmic stimuli shared by nearly all adults.

To test your intuition, next time you see a toddler “dance,” watch very carefully to see how reliably they synchronize their movements to the music. Following my training experience with Ronan the sea lion, I’ve turned a more critical eye to the gyrations produced by my 20-month-old son when I turn on the radio. An adult whose apparent rhythm was so poor would be laughed out of any reputable dance hall post-haste. In fact, there’s good scientific evidence suggesting a lengthy “apprenticeship” underlying human rhythmic abilities. Think of being bounced on a parent’s knee in time to a beat, of the very simple rhythmic patterns we present to younger children, and of how much better at beat keeping trained musicians and dancers are then lay-people. Further, sensitivity to rhythm in adult humans is, at least in part, driven by the type of rhythmic structures we’ve been exposed to in the past. In other words, our apparently spontaneous and effortless beat keeping capability may require a lot more learning (and even training) than we tend to believe. To test this conclusively would require something along the lines of exposing a human who had never heard a beat to simple music and seeing what happened.

But what then of parrots and parrot-type birds? As Jason noted in his original post, there is some reason to believe that the birds shown to keep a beat do not have a history of training. While it’s true that they weren’t trained in an explicit, formal manner as was Ronan the sea lion, the bird subjects studied to date have long, rich histories of human companionship, including extensive exposure to music. To truly conclude that parrots are spontaneous beat keepers, we need to test a naïve parrot without this exposure history. Given the learning curve for human rhythmic capabilities, if parrots turn out to be true, spontaneous beat keepers, this may not represent an overlap with humans, but rather a unique trait, requiring, in turn, another set of new hypotheses attempting to explain why.

Finally, a scientifically irrelevant point of sea lion pride – Jason suggested that Ronan is actually not the first non-human mammal to be shown to beat keep. While it’s true that some elephants appear, from YouTube videos, to be able to keep the beat, Ronan is the first non-human mammal shown, in rigorous and thorough laboratory testing, to be able to flexibly find and keep the beat to music. Sorry pachyderms, Ronan got there first.

Cook P., Rouse A., Wilson M. & Reichmuth C. (2013). A California Sea Lion (Zalophus californianus) Can Keep the Beat: Motor Entrainment to Rhythmic Auditory Stimuli in a Non Vocal Mimic., Journal of Comparative Psychology, DOI: 10.1037/a0032345

Want to get in touch with Peter Cook? Email him: pcook [at] ucsc [dot] edu

Photo by C. Reichmuth, via UCSC News Center.

But this week, I stumbled across a post that chef and writer Michael Ruhlman wrote in May 2012: Why It’s Ethical to Eat Meat. It takes – perhaps unintentionally – a very different approach to the question of conservation psychology.

The crux of his argument seems to be that humans evolved to eat meat. And indeed we have. Cooking, as Richard Wrangham has argued, may have been among the more critical advances in human culture that allowed us to become the species we are today. The reasoning goes that cooking meat allows the human digestive system to capture more calories per bite of meat than it would be able to metabolize from raw meat. That, Wrangham says, allowed our brains to grow, which in turn allowed our societies to grow, since bigger brains meant that we were able to keep track of our friends and enemies more efficiently. Here’s Ruhlman:

…the cooking of food may well have been the mechanism that tripped our ancient genes into our current human ones. He suggests convincingly that consuming calorie-dense food (attainable only by cooking it) grew our brains, gave our ancestors the health needed to spread their genes, and socialized us (cooking food required cooperation, which led to small societies that could organize and protect themselves). Meat was a main source of this calorie-dense food.

To put it as simply as possible, then, to give up eating what made us who we are possibly endangers us genetically and socially.

As a self-described meat eater, I’m not sure I buy this argument. For one thing, it relies on the naturalistic fallacy. Just because something occurs in nature does not make it ethically permissible. Moral or ethical questions of this sort are the result of culture (they might be better thought of as “conventions” rather than “morals”), not of biology.

But Ruhlman goes on to make another argument: “If spit-roasted dodo bird had been delicious to eat, I’d wager the dodo bird would still exist.” And, further down in his post, “…provided the animals are treated with care, our eating them ensures their survival, life’s ultimate impulse, no matter the form.”

I suspect he’s basically right here, at least from a pragmatic gene’s-eye-view perspective.

Ignore, for a moment, the horrific way that a large proportion of factory farming is practiced, at least in America. Pretend that the animals we eat are raised and slaughtered ethically and sustainably. Would “farming” tigers, or elephants, or chimpanzees for human consumption* be an effective conservation tactic? What about critters that were less intelligent (measured against human intelligence, which is admittedly a problematic metric to use), like endangered bats or tree frogs or California condors?

Here’s one thing I know: if it were profitable and they could be ground up and shaped into burgers, McDonalds would have de-extincted the woolly mammoth long ago.

Image via Flickr/Marji Beach.

*Note: Let me be perfectly clear, in order to discourage any wild accusations in the comments, that I’m not advocating for this approach; just engaging in an interesting thought experiment.

Ronan was rescued by the Marine Mammal Center while walking down the Pacific Coast Highway in October 2009. As it was her third stranding incident, she was unreleasable. She was then transferred to the Pinniped Lab at UCSC.

Ronan is the name of a the California sea lion (Zalophus californianus) who can bob her head in time to music. She apparently dances to Boogie Wonderland, and the Backstreet Boys song Everybody. She can move her head in rhythm with the beats of a metronome. She’s in the news this week because a new study from the University of California, Santa Cruz, where she lives after being rescued by the Long Marine Lab, announced that she displays evidence of “rhythmic entrainment,” or the ability to sync the movements of one’s body with an external source of sound or music. I’ve written about this before:

Many species like the bird of paradise have various sorts of mating rituals, which could be described as “dances” by analogy. But dancing means something more specific: the “rhythmic entrainment to music.” Dancing requires that an individual moves his or her arms, legs, and body in sync with a musical beat. All human cultures ever encountered can do this, and until recently we thought this talent or ability was unique to our species. Until, that is, a celebrity parrot named Snowball knocked us off our place of perceived prominence.

This could be really big news. Why?

“…People thought that vocal mimicry might actually be a necessary precondition for rhythmic ability,” the researcher explains in the video abstract above. “But our findings with Ronan, who as a sea lion is not a vocal mimic, challenge that theory.”

Indeed, the prevailing theory is that it isn’t just humans that can dance, but any species capable of vocal learning, which also includes elephants, some bats, songbirds, parrots, hummingbirds, cetaceans like dolphins and whales, and seals. It was Aniruddh D. Patel who forumulated this hypothesis in 2006, writing:

…the foregoing observations can be condensed into a specific and testable hypothesis, namely that having the neural circuitry for complex vocal learning is a necessary prerequisite for the ability to synchronize with an auditory beat. This “vocal learning and rhythmic synchronization hypothesis” predicts that attempts to teach nonhuman primates to synchronize to a beat will not be successful.

Subsequent attempts to look for rhythmic entrainment in rhesus monkeys have indeed not been successful. It was thought that this was because humans are the only primates who have vocal learning. Chimpanzees don’t, bonobos don’t, and neither do gorillas, orangutans, or any of the many monkey species.

In general, sea lions are not considered to be vocal learners. However, operant conditioning experiments with California sea lions conducted in the 1960s showed that sea lions are able to learn and modify vocal responses to external stimuli, and produce or inhibit certain calls in a fairly flexible way. Most vocal calls are thought to be innate and reflexive, not subject to modification by learning nor to subjective control.

“Virtually all marine mammals can be very easily trained to vocalize on command, in stark contrast to any primate or most terrestrial mammals,” Tecumseh Fitch, an expert on the evolution of language and bioacoustics, told me by email. And that is “probably about the need for breath control during diving.”

It’s worth pointing out that part of the confusion may stem from sea lions’ slippery cousins, the seals. “True” or “earless” seals are members of the family Phocidae which includes the famous harbor seal Hoover. They are vocal learners. But another group of pinnipeds is the family Otariidae, or “eared” seals, which includes sea lions and fur seals. The otariids are not typically considered vocal learners, and neither are members of the third group of pinnipeds, the walruses (Odobenidae).

In other words, “true” seals and “eared” seals, which confusingly includes sea lions, diverged around 35 million years ago. That, according to Fitch, means that they are “about as different as cats and dogs.” True seals are vocal learners.

So are sea lions vocal learners or aren’t they? We’ll come back to that in a moment.

First, I would be remiss if I did not point out that while it might make for a snappy headline, Ronan is by no means the first non-human mammal to show evidence of dancing. A 2009 paper by animal cognition researchers found dancing in at least four Asian elephants. Sorry, Ronan.

Still, Ronan’s performance is – potentially – a big blow to Patel’s “vocal learning and rhythmic synchronization hypothesis.” But not as big a blow as a chimpanzee named Ai.

Research published last week in the open-access journal Nature Scientific Reports provided convincing evidence that a 36-year-old female chimpanzee named Ai was able to tap her finger in sync with a beat. Two other chimpanzees, 12-year-old male Ayumu and 12-year-old female Cleo, were unable to sync their tapping with a beat. Still if Patel’s hypothesis was right, then Ai shouldn’t have been able to do this.

The truth is, though, that Ai’s performance was a bit weak. For one thing, she wasn’t able to to synchronize her finger tapping at multiple rates. Humans, for example, are able to synchronize their tapping to rates between 200 and 1800 milliseconds, while Ai was only successful at 600 ms. And while it passed statistical significance, her accuracy wasn’t as good as it could have been.

Most damaging, however, was that there wasn’t conclusive evidence that Ai’s synchronized tapping was the result of entrainment of her motor system to the beat, because the keyboard she was tapping made sounds when the keys were tapped. That means it is possible that Ai just synchronized the sound of the piano with the rhythm, much like musicians do with a metronome, rather than explicitly synchronizing her behavior itself with the rhythm.

What of Patel’s vocal learning and rhythmic synchronization hypothesis? Neither Ronan nor Ai is enough to completely shatter it. Here are some possibilities.

First, Ronan and Ai may simply be extraordinary individuals from among their respective species. Perhaps they’re even capable of vocal learning, at least in a limited way. While this is unlikely, it would leave Patel’s hypothesis intact.

Second, perhaps any animal with sufficient training can learn rhythmic entrainment. While damaging to the vocal learning hypothesis, it would just shift the goalposts slightly – what is it about humans, songbirds, parrots, and the rest that allows them to do this so easily and so flexibly, without extensive training?

There’s a third possibility. I promised to return to the question of whether sea lions are vocal learners, and here is the answer. Perhaps the distinction between vocal learners and non-learners needs to be re-thought. Indeed, the strict dichotomy between vocal learners and non-learners is probably a bit too simplistic to describe biological variation anyway. Perhaps sea lions and chimpanzees (and mice?) lie somewhere in between complete non-mimics like rhesus monkeys and true vocal learners, like humans, parrots, elephants, and the rest of their dance partners. If this is the case, and I believe it is, then the question becomes how sophisticated must vocal learning be before a given species is able to predictably demonstrate dancing ability?

No single scientific experiment provides the last word on anything. Ronan and Ai don’t completely eviscerate Patel’s vocal learning hypothesis, but combined they pose a challenge that must be addressed. That’s how science works. Someone puts forth a hypothesis, and others vigorously try to break it. If they succeed, then after multiple independent replications, the hypothesis needs to be modified. And that’s a far more interesting story than “sea lion learns to dance.” It’s one that plays out over generations with multiple protagonists and plot twists.

Cook P., Rouse A., Wilson M. & Reichmuth C. (2013). A California Sea Lion (Zalophus californianus) Can Keep the Beat: Motor Entrainment to Rhythmic Auditory Stimuli in a Non Vocal Mimic., Journal of Comparative Psychology, DOI: 10.1037/a0032345

Hattori Y., Tomonaga M. & Matsuzawa T. (2013). Spontaneous synchronized tapping to an auditory rhythm in a chimpanzee, Scientific Reports, 3 DOI: 10.1038/srep01566

Patel A.D. (2006). Musical Rhythm, Linguistic Rhythm, and Human Evolution, Music Perception, 24 (1) 99-104. DOI: 10.1525/mp.2006.24.1.99

For more on music and dancing:
Are Humans The Only Species That Enjoy Dancing
Singing Mice Might Join Humans and Songbirds as Vocal Learners
Adventures in Pedantry: Fringe’s Captain Windmark Can’t Be A Toe-Tapper
Day Old Chickens Prefer The Same Music That You Do

For more on pinnipeds:
Forget Elephants. Sea Lions Never Forget!

Ronan photo via Pinniped Cognition and Sensory Systems Laboratory

Here’s an angolan colobus monkey, with some bits of breakfast stuck to its face.

An African Grey Parrot, a conspecific of the famous Alex.

A menacing Steller’s Sea Eagle, the best of all of Steller’s birds, according to John McCormack. (Sorry, Steller’s Jay!)

An Allen’s Swamp Monkey. This primate is the only species in its genus, Allenopithecus.

A domestic camel with a floppy hump.

A female bonobo.

A pair of female bonobos, taking a break from some allogrooming.

With that, I present The Best Animal Photo I Have Ever Taken – a female bonobo photographed on March 3, 2013, at the San Diego Zoo.

Changes are afoot around here! Six new blogs were launched today, which when combined with the previously-existing Sci Am psychology and neuroscience bloggers, form the new Scientific American MIND Blog Network.

What does it mean for this blog? Nothing has changed. All the current feeds and links will remain as they are – instead, you’ll simply be able to find this blog in a few new places, such as the MIND homepage, the MIND Blogs homepage, the MIND facebook page, and the MIND twitter account.

And, you may notice the little MIND icon popping up near the MIND blogs on various pages throughout the Scientific American website.

If you’re new to this blog, I encourage you explore the archives, like me on facebook, follow me on twitter, circle me on Google+. Find out more about me on the about page.

Typically, I post a new article each week on human or animal behavior or cognition. Things have been a bit slow the last few weeks, and will continue to be slow for several more, as I’m spending most of my writing energy on my dissertation. Things should pick up again by mid-May!

Photo: Flamingo at the San Diego Zoo, copyright the author.

This kind of simple-to-complex transformation is not unique to inferring the 3D shape of objects. The mind also works to infer social variables – such as causality and animacy – from simpler inputs, such as actions and movements.

For example, imagine two circles, one red and one green, several inches apart but along the same line. The red circle moves in a straight line until it collides with the green circle. Thanks to physics, we know that when that happens, the red circle stops moving, and the green circle starts moving in the same direction that the red circle had previously been moving.

Now imagine the same two circles. The red circle begins moving towards the green circle, just as before. This time, before it can collide with it, the green circle moves away.

The two scenarios are very similar, but in one case the green circle’s motion was the direct result of a physical impact, while in the second scenario, it was not. Despite the fact that the retinal input from these two displays are extremely similar, you can’t help but think of the circles as “alive” in the second scenario. You might assume that the red circle “wants” to catch the green one, and that the green circle “wants” to run away. Under certain conditions, even 2D shapes can be interpreted as animate social agents rather than simple intentionless objects. In other words, you have imbued the red and green circles with desires and intentions. You have granted them minds.

This phenomenon was perhaps most famously investigated in 1944 by Smith College experimental psychologists Fritz Heider and Marianne Simmel. In their first experiment, the psychologists simply instructed their female undergraduate subjects to “write down what happened” in the movie above. (The rest of this post will only make sense if you watch the video above!)

Most of the thirty four subjects interpreted the shapes in the movie as animate characters. Thirty two described them as people, and two described the shapes as birds. The experimenters provide an example of a common interpretation:

A man has planned to meet a girl and the girl comes along with another man. The first man tells the second to go; the second tells the first, and he shakes his head. Then the two men have a fight, and the girl starts to go into the room to get out of the way and hesitates and finally goes in. She apparently does not want to be with the first man. The first man follows her into the room after having left the second in a rather weakened condition leaning on the wall outside the room. The girl gets worried and races from one corner to the other in the far part of the room. Man number one, after being rather silent for a while, makes several approaches at her; but she gets to the corner across from the door, just as man number two is trying to open it. He evidently got banged around and is still weak from his efforts to open the door. The girl gets out of the room in a sudden dash just as man number two gets the door open. The two chase around the outside of the room together, followed by man number one. But they finally elude him and get away. The first man goes back and tries to open his door, but he is so blinded by rage and frustration that he can not open it. So he butts it open and in a really mad dash around the room he breaks in first one wall and then another.

They also provide an unusually elaborate interpretation made by one subject:

The first thing we see in this little episode is triangle number-one closing the door of his square. Let’s insist that the action of the play is on a two-dimensional surface (not that it makes much difference) and we will undoubtedly start calling the square in which the triangle number- one seems to make his dwelling, a house, which infers three dimensions. But we are not sticking to the theme of our story. Triangle number-one shuts his door (or should we say line) and the two innocent young things walk in. Lovers in the two-dimensional world, no doubt; little triangle number-two and sweet circle. Triangle-one (here-after known as the villain) spies the young love. Ah! … He opens his door, walks out to see our hero and his sweet. But our hero does not like the interruption (we regret that our actual knowledge of what went on at this particular moment is slightly hazy, I believe we didn’t get the exact conversation), he attack striangle-one rather vigorously (maybe the big bully said some bad word).

There were some common themes. For example, nearly every subject described the interaction between the big triangle and the small triangle as a fight. Most described the big triangle being locked in the “house.” The interaction between the big triangle and the circle was usually described as a chase. And the “door” was almost always controlled by the shapes; the shapes were never moved by the door.

Of thirty four subjects, only one described the film in strictly geometrical terms. She wrote:

A large solid triangle is shown entering a rectangle. It enters and comes out of this rectangle, and each time the corner and one-half of one of the sides of the rectangle form an opening. Then another, smaller triangle and a circle appear on the scene. The circle enters the rectangle while the larger triangle is within. The two move about in circular motion and then the circle goes out of the opening and joins the smaller triangle which has been moving around outside the rectangle. Then the smaller triangle and the circle move about together and when the larger triangle comes out of the rectangle and approaches them, they move rapidly in a circle around the rectangle and disappear. The larger triangle, now alone, moves about the opening of the rectangle and finally goes through the opening to the inside. He moves rapidly within, and, finding no opening, breaks through the sides and disappears.

Having verified that humans spontaneously thought of the shapes in their video as animate, Heider and Simmel showed the film to another thirty six undergraduate students. They were explicitly asked to describe the personalities and desires of each of the shapes.

Thirty five of them thought of the big triangle as mean, and used adjectives like aggressive, warlike, belligerent, quarrelsome, angry, bad-tempered, dominant, and irritable. They described it as a bully or as a villain, and they thought it enjoyed “picking on smaller people.” Tellingly, it was universally described using male pronouns.

There was slightly more variation when it came to interpretations of the personalities of the small triangle and the circle.

Seventy five percent thought that the circle was afraid, fearful, cowardly, shy, timid, or meek. It was described as a follower, reliant on the small triangle for protection. Sixty one percent described the circle using female pronouns. Only a few described the circle as clever or shrewd.

The small triangle was described by half the participants as heroic, valiant, brave, courageous, or defiant. Many interpreted its actions as the result of resentment at being bullied by the big triangle. The experimenters reason that the small triangle is thought of as brave because, unlike the circle, it hits back and defends itself against the big triangle. Like the circle, a third of participants described the small triangle as clever, brainy, or intelligent. And like the big triangle, the small triangle was almost universally referred to as male.

In both experiments, subjects interpreted individual interactions in fairly routine ways as well. For example, they thought that when the circle and small triangle spun around eachother, it was an expression of joy. And when the circle was trapped in the house with the big triangle, most subjects understood her actions as evasive, reflecting her fear of the bully.

Importantly, the order in which the events were displayed predicted the sorts of personalities and intentions attributed to the shapes. When the experimenters played the movie in reverse for a third set of subjects, their responses were very different from the subjects in the first two experiments.

For example, several times in the video the big triangle and circle move in and out of the house. The motivations behind those actions would differ depending on the order in which the movements occurred. When the shapes’ actions were thought of as spontaneous, they might be described as “hiding” or “escaping.” But when the actions were interpreted as reactions, the very same motions might be described as “being forced in” or “being lured in.” The interpretation of the social interaction would depend on whether the film was played in forward or in reverse. What that means is that the order in which actions occur is critical to the way we interpret motivations, intentions, and desires.

The process through which we attribute mental characteristics to animated circles and triangles is a powerful example of a certain kind of anthropomorphism, a process through which we infer the unobservable mental features of non-human agents as human-like.

Which leads to a chilling question. If it is so easy to imbue geometric shapes with human-like thoughts, feelings, intentions, and desires, how is it equally easy for some people to view others of their own species as decidedly non-human?

Heider F. & Simmel M. (1944). An Experimental Study of Apparent Behavior, The American Journal of Psychology, 57 (2) 243. DOI: 10.2307/1416950

Scholl B.J. & Tremoulet P.D. (2000). Perceptual causality and animacy, Trends in Cognitive Sciences, 4 (8) 299-309. DOI: 10.1016/S1364-6613(00)01506-0

Images: Eye diagram via Ruth Lawson/Wikimedia Commons. Circles diagram modified from Scholl & Tremoulet (2000).

My latest piece for BBC Future is now up, and it focuses on how the things we may think of as odd, gross, or strange when it comes to human sexual practices are perhaps entirely normal for other species.

Romantic relationships are complicated, and so is sex. Relationships can be fraught with the potential for miscommunication or misunderstanding at the best of times, so imagine how troublesome it is to admit, out loud, to your partner, that you’ve got a sexual interest or fantasy that sits far outside the cultural norms.

But here’s a secret. For just about any fantasy between consenting adults that might be thought of as beyond conventional sexual practices or decency as dictated by society, you can bet that there’s a non-human species for whom that particular behaviour is commonplace. Sure, there are plenty of examples of creative role-playing, food in the bedroom, or unusual places to do the deed, but even when you push the boundaries much further the chances are you’ll find it happening in the animal world.

Click on over and check out the rest. There are giraffes, hippos, sharks, snakes, and even a cephalopod or two. Think of it as fifty shades of animal grey.

Photo copyright the author.

Tomorrow night, Friday February 22 at 7:30pm, Cinefamily and and Cinespia Salon will present the latest installment of the their Science on Screen series at the old Silent Movie Theater in Los Angeles. The evening’s screening will feature an independent film called Bestiaire.

A truly breathtaking exploration of interspecies observation, Bestiaire is the rare documentary that’s subdued and meditative to the point of sensory-deprivation, but also suffused with so much depth and mystery that it’s impossible to turn your eyes away. Shot by celebrated documentarian Denis Côté in Hemmingford, Quebec’s Parc Safari animal sanctuary over the course of several months, Bestiaire simply captures extended tableau of Parc Safari’s creatures doing the actions that they do, as well as their human handlers in the act of tending to them. This visually stunning montage is especially remarkable because it has no deliberate agenda: no interviews, no narration, no sentimentality — and no overt political bent to color its scenes. Every moment is composed like a painting, and each subject is captured by the camera as though in the middle of intense, deliberate choreography. Lingering and drifting into each other in a startling way, these mini-chapters’ gentle intensity accumulates into an experience that will likely be cohesive in a completely different way for every person who takes them in. Potent stuff, in one of the greatest docs of the year.

Following the screening, I’ll be doing a Q&A with Cinefamily director Hadrian Belove about the role of non-human animals in human culture, and then art gallery Mastodon Mesa will throw a back patio party featuring taxidermy, wildlife education, a drawing session, and more. I think that the film is an interesting commentary on typical natural documentaries, but I have my own opinions about whether or not the film truly has “no deliberate agenda.” It should make for an interesting conversation.

The show also includes Rachel Mayeri’s short Primate Cinema: Apes As Family (which just premiered at Sundance 2013) and Nicolas Provost’s Moving Stories (the short which played before screenings of Bestiaire at Sundance 2012!)

Doors open at 7pm and the screening begins at 7:30. Tickets are $12 and may be purchased here.

Related:
Putting Science on Screen (A Tale Told In Tweets)

One study conducted in Canada, for example, found that in their project notebooks, students “frequently attended to claims-making practices recommended in science education literature, especially involving argumentation and concepts of evidence,” and that their conclusions “were often supported through the use of replication, triangulation, and often statistical analysis, with their findings embedded in a broader research literature.” In other words, students appeared to be using the same sorts of reasoning processes upon which scientists rely. The researchers concluded that students who participated in science fairs successfully learned “many of the normative practices of science investigation.”

But that’s for students who are already participating in science fairs. It is perhaps of greater importance that science fairs be able to reach those students who might not already eagerly participate whether due to motivation or circumstance. As Bora Zivkovic noted several years ago,

How do we increase scientific knowledge and understanding of the general population? No matter how good we are at science reporting and science communication as a whole – this will not matter as long as this is a “pull” culture and most people will never get to see any of that science communication anyway, be it good or bad.

And, as Danielle Lee wrote recently,

For kids like my students – inner-city kids from poor families (whether working-class or on welfare), average or below-average academic performance, some with behavior problems – interests in STEM (science, technology, engineering, math) dies by 10th grade and one of three things kill the promise of opportunity.

Indeed, the researchers in the study mentioned above pointed out that they observed “significant signs of most participants’ elite status. For instance, students appeared to dress and speak well, and many seemed to have access to relatively expensive technologies, such as cell phones and laptop computers. It was not unusual, according to interviews, for students to spend hundreds of dollars on preparing their display—and some even utilised graphic design firms to maximise their impact.” Only one student that they interviewed after a 2005 fair reported that he had dial-up internet at home; the rest had high-speed access. Not to mention the financial resources to purchase supplies and equipment, and the social support from their friends, teachers, and parents.

Meanwhile, a recent count indicated that in Los Angeles County, more than one million K-12 students receive free or reduced price meals – a whopping 65% of the total enrollment. Nearly a quarter of all students in LA County are English language learners.

These are students who will increasingly require basic scientific literacy if they are to become informed, healthy, voting members of society. These students – like all students – need to understand basic ideas governing health, medicine, and the way their own bodies work. They need to understand where the energy that powers their refrigerators and cell phones and cars comes from.

In America, it is generally during high school that we solidify our own perceptions of our selves. In a recent New York Magazine feature, Jennifer Senior pointed out,

Our self-image from those years, in other words, is especially adhesive. So, too, are our preferences. “There’s no reason why, at the age of 60, I should still be listening to the Allman Brothers,” [Laurence Steinberg, a developmental psychologist at Temple University] says. “Yet no matter how old you are, the music you listen to for the rest of your life is probably what you listened to when you were an adolescent.” Only extremely recent advances in neuroscience have begun to help explain why.

It turns out that just before adolescence, the prefrontal cortex—the part of the brain that governs our ability to reason, grasp abstractions, control impulses, and self-­reflect—undergoes a huge flurry of activity, giving young adults the intellectual capacity to form an identity, to develop the notion of a self. Any cultural stimuli we are exposed to during puberty can, therefore, make more of an impression, because we’re now perceiving them discerningly and metacognitively as things to sweep into our self-concepts or reject (I am the kind of person who likes the Allman Brothers). “During times when your identity is in transition,” says Steinberg, “it’s possible you store memories better than you do in times of stability.”

Access to scientific information – or inaccess to scientific information – has real, tangible consequences. The relationship that children and adolescents have to science will likely stick with them for the rest of their adult lives.

The LA County Science Fair has a rich history. By 2010, the fair grew so big that it was moved to a larger space – the Pasadena Convention Center. That year, there were 1500 projects, and projects presented by young women outnumbered those presented by young men by thirty percent!

On the surface, this is great news. But all of this is a preamble to the following.

I woke up this morning to an alarming-if-unsurprising email from Dean Gilbert, President of the Los Angeles County Science Fair Committee. This year’s science fair, scheduled for next month, may not even happen due to fundraising shortfalls, and as a result, a 2014 science fair has not yet been scheduled.

Wednesday night at the monthly Science Fair Advisory Board meeting, I stated that as of right now, having the 2013 Los Angeles County Science Fair is in serious question and that there will be no Science Fair scheduled for 2014. This is because we are $70,000 short of our current year fundraising goal and still need another 150 judges.

If you’re in the LA area, consider registering to become a judge. I have.

If you’d like to support the LA Count Science Fair financially, click on the “Donate” button here. As they say, every dollar counts.

The Los Angeles County Science Fair is a 501 (c)(3) non-profit organization funded solely through contributions from businesses, corporations, foundations, elected officials, and private parties. Donations are tax-deductible.

Disclosure: Other than having registered as a judge, I am in no way associated with the LA County Science Fair.

Mindshare LA Presents: “Your Primal Instincts” …on the West Side!

I’ll be speaking at a special sciencey Valentine’s Day version of Mindshare this month in Santa Monica along with Christopher Ryan (of Sex at Dawn fame) and science journalist Sharon Brock.

We’ll all be covering the science of love from our own perspectives, and my talk will be about how animals shout at each other for sex, how some types of shouts are more effective than other types of shouts, and what (if anything) it might tell us about how we humans go about finding that special someone.

Animals have adopted all sorts of special skills to survive but some of the most interesting behaviors surround their mating strategies. Ostentatious plumage, fancy footsteps and even arguably artists skills are found in nature. This talk will explore how animals attract mates using their calls… and what it might teach us about our own mating strategies.

Ever wanted to know what a bison sounds like when he’s trying to seduce a lady bison? Come out next Wednesday, and you’ll find out!

The event is 7pm-11pm, Wednesday, February 20th, at VLounge.

Tickets will sell out – I’m told there very few remaining – so if you’d like to come, reserve your tickets ASAP.

In the photo above, Koko the gorilla plays with a doll, apparently pretending to nurse it. But can non-human animals really pretend? Do they have the ability to imagine? Can animals carry themselves to worlds that never were, as human children routinely do? These are the questions I explore in my latest piece at BBC Future:

An eight-year-old juvenile chimpanzee named Kakama trudged along a path among the forest trees, following his pregnant mother. A scientist sat silently at a distance, watching Kakama pick up a log and carry it with him for hours. At one point, Kakama made a nest and placed the log in it, as if it were a small chimpanzee. Months later, two field assistants observed the same thing: Kakama was playing with a similar log, which they labelled “Kakama’s toy baby.”

Click over to my BBC future column to read the rest, including plenty more charming stories of animal imagination: Do animals have imagination? (Here’s a UK-friendly link.)

Image via Koko.org

What responsibilities do filmmakers have in terms of scientific accuracy? Usually, I argue that filmmakers are storytellers first, and while scientific accuracy (or plausibility) can often support a narrative, the first responsibility of the filmmaker is to weave a captivating tale. But what happens when the film (or TV series) in question is overtly scientific in nature?

It might be a straightforward nature documentary like BBC’s Planet Earth or National Geographic’s Great Migrations, or it could be a docu-drama – a narrative derived from clever editing of thousands of hours of footage of wild animals paired with heart-tugging voiceovers – like March of the Penguins or Disney’s Chimpanzee.

In these cases, filmmakers might have a higher obligation to get the science right, which poses a unique science communication challenge.

Yesterday, Cristina Russo wrote a post about some of these issues at the PLoS Blog Sci-Ed, which sparked a twitter conversation, which I’ve compiled into a storify. Add your own thoughts in the comments below, on twitter or on Google+.

The triumph of corvids over numbers yesterday in the Super Bowl meant two things to me: first, that ornithology continues to trounce math in any contest that matters, and second, that I would have to follow up this weekend’s groundhog post with a post about the amazingness of one of the most clever of winged critters.

Here, then, are six seven things you didn’t know about ravens.

A corvid family tree. There are 120 bird species in the corvid family, which includes crows, ravens, magpies, jays, jackdaws, and rooks. There are actually ten species of raven! The two extinct raven species are called the Chatham Raven (Corvus moriorum) and the New Zealand Raven (Corvus antipodum). Among living ravens, there are so many more than the Common Raven (Corvus corax), which is appropriately the most common sort of raven, occurring across the northern hemisphere. Other types of ravens include: White-necked Ravens (Corvus albicollis), Australian Ravens (Corvus coronoides), Thick-billed Ravens (Corvis crassirostris), Chihuahuan Ravens (Corvus cryptoleucus), Little Ravens (Coruvs mellori), Fan-tailed Ravens (Corvus rhipidurus), Brown-necked Ravens (Corvus ruficollis), and Forest Ravens (Corvus tasmanicus).

Loyalty among birds. Ravens, like all other corvids, are monogamous, and the bond typically lasts for life. Ravens select their partners in the autumn, following impressive acrobatic displays. Following pairing, the duo preen eachother, and usually support each other in aggressive interactions with other ravens. Here’s what raven mating looks like:

Privacy, please! Raven pairs prefer to maintain a large territory for themselves, keeping interlopers away from their nest. In general, their territories last for life.

Adolescent rebellion. When ravens emerge from childhood and become teenage corvids, they usually leave their parents’ territory and are known to join with other adolescent runaways, forming teenage gangs. While it may be easier for a group of thirty young ravens to find a carcass to feed on, life in a gang is stressful. Scientists think that, eventually, the releatively stress-less bliss of monogamy outweighs the benefits of group living.

Farm-to-table menu. Like many new-age foodies, ravens only forage for their eats within their own territories, making them true locavores.

Theory of mind. Ravens, like other corvids, are known to cache their food. And when they do it, they try to hide their caches in locations that nearby others can’t see, like behind rocks or trees. This suggests that ravens are able to engage in “visual perspective taking,” or knowing what another raven can and can’t see, a basic form of theory of mind.

Playtime is for the birds. Even ravens like to play sometimes. In particular, they seem to enjoy using their bodies as sleds. In Play in common ravens, University of Vermont biologists Bernd Heinrich and Rachel Smolker point out that ravens do this quite a bit: “Observers from Alaskan and Northern Canadian towns routinely reported to us seeing ravens slide down steep snow covered roofs, only to fly or walk back up and repeat the slide. Ravens in our Maine aviary also roll down mounds of snow, and even do so on their backs with a stick held in the feet! David Lidstone, observing ravens at a deer carcass in Maine during the first snow storm of the year, reported that ‘at least three birds flew up to a stump on a 2-3m incline, and then slid down the slope on their backs.’”

For more on corvids:
Snowboarding Crows: The Plot Thickens

Clayton N.S. & Emery N.J. (2007). The social life of corvids, Current Biology, 17 (16) R652-R656. DOI: 10.1016/j.cub.2007.05.070

Image via Wikimedia Commons/Cj005257.

Happy Groundhog Day! Today is the day each year in which we look towards a giant rodent to find out how much more winter we’ll have to endure. This year, we probably know the answer: winter hasn’t been very wintery, even for Los Angeles. Raleigh, on the other hand, is freezing for this LA boy.

According to tradition, the groundhog (Marmota monax) peeks out of its burrow today, and checks to see if it has a shadow. If sunny enough for a shadow, the groundhog will return to the comfort of its burrow, and winter will continue for an additional six weeks.

In honor of the holiday, I’ve rounded up eight things about groundhogs that you probably didn’t know.

1. A groundhog by any other name. Groundhogs are also variously referred to as woodchucks, whistle-pigs, land-beavers, or marmots. The name whistle-pig comes from the fact that, when alarmed, a groundhog will emit a high-pitched whistle as a warning to the rest of his or her colony. The name woodchuck has nothing to do with wood. Or chucking. It is derived from the Algonquian name for the critters, wuchak.

2. Home sweet home. Both male and female groundhogs tend to occupy the same territories year after year. For females, there is very little overlap between home ranges except for the late spring and early summer, as females try to expand their territories. During this time, their ranges may overlap by as much as ten percent. Males have non-overlapping territories as well, though any male territory coincides with one to three mature females’ territories.

3. Baby groundhogs! Infants stick around home for only about two to three months after being born in mid-April, and then they disperse and leave mom’s burrow. However, a significant proportion – thirty five percent – of females stick around longer, leaving home just after their first birthdays, right before mom’s new litter arrives.

4. Family values. In general, groundhog social groups consist of one adult male and two adult females, each with an offspring from the previous breeding season (usually female), and the current litter of infants. Interactions within a female’s group are generally friendly. But interactions between female groups – even when those groups are shared by the same adult male – are rare and aggressive. Even though daddy woodchuck doesn’t live at home, from the breeding season through the first month of the infants’ lives, he visits each of his female groups every day.

5. Medical models. Groundhogs happen to be a good animal model for the study of hepatitis B-induced liver cancer. In fact, if infected with Woodchuck Hepatitis B virus, the animal will always go on to develop liver cancer, making them useful for the study both of liver cancer and of hepatitis B.

6. Look up! Though they spend most of their time on or under the ground, groundhogs can also climb trees.

7. Eskimo kisses. Groundhogs greet each other with an odd variation of the eskimo kiss: one groundhog approaches and touches his or her nose to the mouth of the second groundhog. Or, as scientists call it, they make “naso-oral contact.”

8. Marmots everywhere! There are – count ‘em – fourteen species of marmot found throughout the Northern Hemisphere.

Meier, P. (1992). Social organization of woodchucks (Marmota monax) Behavioral Ecology and Sociobiology, 31 (6) DOI: 10.1007/BF00170606

Photo: Wikimedia Commons/April King.

Among animal welfare professionals, those who work at zoos might have the toughest jobs. Keepers and curators at zoo must alternately serve as biologists, psychologists, trainers, chefs, janitors, and educators. Often, those hardworking individuals take on multiple roles at once. Another important job that keepers and curators perform at the zoo is that of gerontologist. Gerontology, or the study of aging, is a field that has only been formally defined for forty years, and is becoming a more important consideration for the welfare of captive animals.

With the exception of animals raised in a specific breeding program who are destined for reintroduction, animals that are born in zoos will typically live out their lives, and ultimately die, in zoos. Zoos need to therefore adequately prepare to deliver proper care – both physical and psychological – for their aging residents. Providing that sort of proper veterinary care might involve making adjustments to an animal’s environment, routine, or social groupings. Those changes, while made in the service of an animal’s welfare, could nonetheless result in psychological distress.

Like any health care provider, a zoo’s animal care staff has to balance the medical health requirements of their charges with their psychological well-being. Human doctors can simply ask their patients how they feel; veterinarians do not have this option. Instead, zoo researchers conduct detailed observations of their animals to determine what consequences might follow any major change in management procedures.

Tigers are typically thought of as solitary creatures. In the wild, according to common knowledge, if you see two or more tigers together (and it isn’t mating season), you can bet its a mother and her cubs. However, the social systems of big cats may be more malleable than once thought. There is evidence, for example, that wild tigers gather in temporary aggregations to feast on a recent kill. And other large cats like cheetahs and snow leopards, despite being thought of as solitary in the wild, have been well-suited to social housing in zoos.

So, what happens when you take a species that is traditionally thought of as solitary, house them socially their entire lives, but then need to separate them on occasion as they become elderly? Disney’s Animal Kingdom is home to six adult female tigers (Panthera tigris). They were originally born into three different litters in the spring of 1997 and were then transferred together to Disney in the Fall of 1998, where they’ve been socially housed ever since. But the tigers are aging. In captivity, tigers live on average twenty years (and fifteen years in the wild), meaning that the sixteen-year-old Disney tigers are in their golden years, and will increasingly require specialized veterinary care.

The Animal Kingdom’s keepers and curators have found that providing personalized medical care or enrichment, or allowing slow eaters more time to eat their food, requires that they separate the tigers overnight. Therefore, while the tigers sleep most nights in groups of three, they sleep individually two nights each week. As they continue to age and become more susceptible to illness, the frequency of nights spent alone may increase. The researchers at Disney’s zoo wondered if the social separation was a stressful experience for their tigers.

Over the course of four three-month periods spread out over two years, the night staff conducted observations of each tiger on four nights per week: two nights in which the tigers were kept apart (though their enclosures still allowed them to see, hear, and smell each other), and two nights when they remained in groups. With two observation periods per night, the researchers had 369 total observations.

Most importantly, they found that the tigers slept the same amount of time – seventy-five percent of the time – whether they were housed together or alone. Sleeping behavior is an important marker of stress, so this was a good sign. Brief periods of social isolation did not seem particularly stressful for the cats. In other words, even if being alone was slightly stressful, it was not severe enough to impact their sleep. And there were no differences in sleeping position, either.

Other indicators of stress such as pacing, a common behavior seen in stressed big cats, or door pounding occurred extremely rarely, and did not occur more often while the tigers slept solo.

When it came to other questions about the tigers’ behavior across conditions, the differences that did emerge were either expected or unimportant.

For example, whether in groups or by themselves they spent the least amount of the time they were awake in a sitting position. But they took up this position more often while individually housed, 1.68% of the time, than while socially housed, when they sat for only 0.79% of the time. While this is a statistically significant difference, the researchers don’t think that it “reflects a significant impact to welfare.” In other words, it doesn’t really matter.

The tigers chuffed more often while together than while alone. This makes sense and would be expected, as chuffing is a social vocalization. They were more likely to groom themselves while alone than while together, but self-grooming is typically thought of as an indicator of positive welfare in big cats. Further, the night keepers did not observe any signs of over-grooming, which, like pacing, would have suggested a negative reaction to their isolation.

Overall, the tigers adjusted quite well to their occasional nighttime separation. As they continue to age and will probably require more nights spent alone, the keepers can rest a bit easier knowing that providing the tigers with better, more personalized veterinary care will not come at the cost of their psychological well-being.

Miller A., Leighty K.A. & Bettinger T.L. (2013). Behavioral Analysis of Tiger Night Housing Practices, Zoo Biology, 1-6. DOI: 10.1002/zoo.21057

Header photo: a tiger yawns at Disney’s Animal Kingdom via Flickr/trenchfoot; Second photo: Malayan Tiger (Panthera tigris malayensis) at the San Diego Zoo copyright the author.

Last week saw the third-to-last episode of Fox’s sci-fi family drama Fringe. Despite the somewhat wonky fifth season, for me Fringe has represented the best sci-fi offering on network television since Joss Whedon’s Dollhouse was cancelled.

For the uninitiated, here’s a bit of background (lots more here) required for today’s pedantic adventure. Warning if you haven’t seen last week’s episode: spoilers ahead. If you’re already current on Fringe, skip past the background.

In the year 2167, a Norwegian scientist found that he could genetically enhance the mental abilities of humans, but the increased intelligence came at the loss of certain emotions. Parts of the brain that had once served as the basis for the human emotional experience had been reallocated for logic, reason, and higher thought. Imagine a brain that’s mostly prefrontal cortex with an underdeveloped limbic system. The eventual success of the experiment led to the emergence of very smart yet emotionless humans.

These altered humans could not experience happiness, grief, jealousy, or anger. They had no sex drive, and thus could not reproduce. To remedy the problem, the future humans developed a technology that would grow new humans in a sort of hydroponic farm. These individuals were known to the protagonists of the show as The Observers. Thanks to this technology, Observers were typically born as fully mature adults.

Sometime in that future, the Observers made the Earth unlivable, ostensibly due to anthropogenic climate change and pollution. The Observers, aided by technology, decided to solve their problem by traveling back in time to the year 2015, where they could colonize the Earth and prevent the future environmental destruction of the planet. In the year 2036, our heroes are rapidly running out of time to enact The Plan which they hope will finally defeat The Observers and send them back to their own time.

Captain Windmark, chief executive of The Observers, stumbles upon a stereo while hunting down our heroes Peter, Olivia, Walter, and Astrid in an effort to prevent them from carrying out The Plan. He plays the music, cocks his head to the side like a lizard, and listens. The camera cuts to a shot of Windmark tapping his toes in rhythm with the music. Back to Windmark’s face, looking vaguely confused.

Captain Windmark, played by Michael Kopsa

The inference we are meant to make is this: despite the genetic alterations that gave The Observers their advanced intellect at the expense of their emotions, even Windmark can’t escape his humanity. Underneath all the tech and all the genetic engineering, he can still be moved by a piece of music. Maybe, then, he isn’t hunting down our heroes solely because it’s the rational thing to do. Maybe he hates them. Even The Observers can’t outrun their emotions.

Here’s the problem. The Observers should not be able to dance.

Dancing, it turns out, is intimately connected to vocal learning. And if The Observers are born as fully mature adults, then for them, language must be innate and unlearned.

In 2009, a group of researchers sifted through hundreds of YouTube videos that claimed to contain evidence of dancing animals, including ferrets, dogs, horses, pigeons, cats, fish, lizards, snakes, owls, camels, chimpanzees, turtles, ducks, hamsters, penguins, and bears. The researchers measured how well the motion of the animals’ bodies mirrored the rhythm of the music being placed. At the end of their analysis, the only videos that passed the synchronization test were ones that contained animals who were vocal learners. In all, the researchers found dancing in fourteen species of parrot, and in an Asian elephant. That’s not to say that all those other species don’t vocalize; of course they do. But their vocalizations are innate, not learned. Just like The Observers.

I’ll concede the possibility that The Observers have some sort of Observer School where they rapidly learn language following their “birth,” which, technically, would classify them as vocal learners, capable of dancing. But even if that were true, there’s more.

Entrainment, or the ability to synchronize one’s body movements to an external rhythm, can happen without explicit effort. Living among modern humans during the twenty-one years since The Invasion, Captain Windmark must have encountered some form of “external rhythm,” at least once. That he was surprised by his toe-tapping suggests that dancing was a new activity for him. If he was capable of dancing, surely at some point, he would have spontaneously – without explicit planning – bounced his head or tapped his toes in the two decades he spent surrounded by the human culture he was so intent on destroying. In a 2010 paper, psychologists Marcel Zentner and Tuomas Eerola point out, “one of the most curious effects of music is that it compels us to move in synchrony with its beat. This behavior, also referred to as entrainment, includes spontaneous or deliberate finger and foot tapping, head nodding, and body swaying.”

In their study, 120 human infants between the ages of 5 months and 2 years were placed on a parent’s lap where they listened to a music clip (the parents were given noise cancelling headphones, so they could not accidentally guide the infants’ actions). The researchers filmed the infants’ movements, and analyzed them, much as the first research group had done with the animal videos.

Zentner and Eerola found that the infants easily entrained their motions to the rhythm of the songs that they heard, whether it was Mozart, a childrens’ song, a simple tune, or even just a rhythmic drum solo. They spontaneously modulated their movements according to increases or decreases in tempo.

And the more synchronized they were, the more they displayed “positive affect.” In other words, dancing made them happy.

Dancing, or more accurately, rhythmic entrainment, is an unlearned response to an external stimulus that occurs in members of species that have vocal learning, and that – at least among humans – results in increased happiness. This leaves us with three possible reasons that make Windmark’s dance entirely impossible, or at least not a reflection of growing emotions.

First, not being a vocal learner, he should not have been able to tap his toes in sync with the song.

Second, even if we granted that Windmark was a vocal learner, capable of dancing, then he should not have been surprised by his toe-tapping, since entrainment is involuntary and he had surely been previously exposed to external rhythms.

Third, even if we granted that The Observers have vocal learning, and that Windmark’s confusion can be explained by having never encountered music – not even an errant rhythmic drumbeat during his more than two decades surrounded by human culture – then dancing is still not evidence of emotion. Zentner and Eerola put it this way: “what may have generated positive affect in our infants is the interoceptive feedback from moving in time with rhythmic pulses.” In other words, the emotional response was a consequence of dancing; dancing is not, itself, derived from emotion.

Update: The big bad himself, Captain Windmark (Michael Kopsa) appears in the comments to tell us that it was the other Observer who was toe-tapping. I maintain that my criticism remains intact, even if applied to the other Observer.

Related:
Lords of the dance: Are humans the only species that enjoy dancing?

Header image via Fox Broadcasting Co; Windmark photo from a screenshot of Season 5, episode 3, “The Recordist.”

Why do animals like to play? Scientists have often used the word play simply to describe any behavior that does not have any apparent adaptive function. In The Animal Mind, James L. Gould and Carol Grant Gould describe play as an “apparently purposeless activity with no immediate adaptive goal, utilizing species-typical motor programs that are exaggerated in intensity or number of repetitions, or misordered compared to mature behaviour, or mixed together with behaviour appropriate to different contexts.”

Writing in The American Naturalist in 1974, Robert Fagen provided a similar account for what constitutes play. When an animal exhibits an “active, oriented behavior whose structure is highly variable, which apparently lacks immediate purpose,” according to Fagen, you might reasonably argue that the animal is playing.

The natural world is rife with such “purposeless activities,” but might there be a deeper purpose to play than simple joy? It’s one thing to figure out what sorts of activities qualify as play, but another to figure out what they’re for. Find out the answers to these questions in my latest column at BBC Future: Why do animals like to play?

And, in case you’ve missed them, here are links to the previous pieces in my BBC Future column, Uniquely Human:
Why animals also seek teenage kicks.
Animals that can count.
Election day, animal style: How democracy works in nature.
Lords of the dance: Are humans the only species that enjoy dancing?
Is language unique to humans?
Pay attention… time for lessons at animal school.
Death rituals in the animal kingdom.

Image: Argo, a border terrier, displays a “play bow.” Copyright the author.