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The Wisdom of the Aged: Matriarch Elephants Lead with Experience

As many people know, African elephants (Loxodonta africana) live in complex matrilineal societies, with closely-knit family groups led by a matriarch who is typically the oldest and largest female in the family. In order to appreciate the importance of these matriarchs, it may help to first consider a traditional Japanese folktale:

Once there was an arrogant young village lord who, deciding that old people were useless, banished them to the mountains to die. Although the villagers were distressed, they obeyed rather than face severe punishment. One young farmer couldn’t bear to follow this cruel decree, though, and hid his aged mother away in a safe and secret room.

Several years later, an invader arrived, announcing that he’d spare the village only if three tasks could be performed. First, he must be presented with a box containing one thousand ropes of ash. Next, a silk thread must be drawn through a small hole that bent seven times along the length of a log. Finally, he must be given a drum that sounded without being beaten.

In each case, the village lord offered rewards, cajoled and threatened the townspeople, but nobody knew what to do; all were in despair. The tasks all seemed impossible. Each time, though, the farmer asked his mother and she knew the answer: soak ordinary rope in salt water before burning it; tie the silk thread to an ant at one end of the hole and place sugar at the other; put a bumblebee in a drum and it will buzz as it tries to escape. The village was spared.

Ultimately, the lord finds out that they have all been saved by the wise old mother, and from that time on elders in the village are revered.

Shifting scenes now from the mountains of long-ago Japan to the plains of today’s Africa, it turns out that older matriarch elephants are much like the heroic old Japanese mother – they are the ones with the answers, the ones that can save their fellow elephants from outside threats with the wisdom they have accumulated through experience.

Listen to your Grandmother! (image copyright ElephantVoices)

As we know from the decades of observation and research performed by Cynthia Moss and her colleagues in Kenya and Tanzania, matriarch elephants act as group leaders, holding together their families and providing behavioral guidance during times of crisis. Many observers believe that the oldest matriarchs – those with the most experience and greatest ecological knowledge – make the best decisions, but until recently it has proved to be difficult to quantify the relevant skills in a manner conducive to experimental testing.

In a March 2011 paper published online in the Proceedings of the Royal Society B, however, a team of scientists led by Karen McComb of the University of Sussex reported on a clever set of experiments that tested whether older Amboseli National Park matriarchs were better than their younger counterparts at assessing the perceived threat posed by various lion roar recordings.

While African elephants are able to fend off most natural predators, they have to watch out for lions, who occasionally prey upon younger calves. Also, even though lionesses perform the, ahem, lion’s share of the hunting for the pride, male lions actually pose a greater threat to elephants. Male lions, despite their generally well-deserved reputation for laziness, are, on average, half again as large as females and much stronger, giving them a better chance of overpowering a vulnerable young elephant.

Accordingly, the researchers assembled lion “playbacks” in four separate categories – single female roars, single male roars, three female group roars and three male group roars – which they then played to 39 elephant family groups over a period of slightly more than two years. Because of the extensive demographic information compiled by the Amboseli Elephant Research Project, they knew the age of the matriarch in each of the 39 families.

After playing the different roars, the researchers analyzed video of the elephants’ responses, focusing particularly on the behavior of the matriarchs. They documented specific defensive reactions, including prolonged listening to the roars, whether the family bunched around the matriarch after hearing the roars, the speed and intensity of any bunching behavior, and whether the matriarch changed her direction and moved toward the source of the playback.

Here are two brief videos, one showing an elephant family reacting to lion roars and the other narratively describing the reactions as reflected in still images:

After recording all of the responses, the research team performed statistical analyses and sorted their results by matriarch age. They found that, while matriarch age did not have an impact on how the elephants reacted to varying number of lions (all elephant families consistently ratcheted up the intensity of their response when the number of lions roaring went from one to three), it did have a strong impact on the elephants’ response to the more serious threat presented by male lion roars, with male roars leading to more prolonged listening and intensive defensive bunching in families led by older matriarchs.

As the researchers put it:

Our work provides the first direct experimental evidence that older matriarchs are in fact able to make better decisions when faced with ecological challenges — in this case, the presence of dangerous predators. It thus bridges an important gap between theoretical predictions about how knowledge might be expected to affect leadership and empirical studies, which to date have been largely confined to observational accounts.

Based on these findings, I’m quite confident that the older matriarchs will do quite well on their next set of tasks involving burning ropes, crooked logs and drums. Now, if only that was enough to keep humans from invading their villages….

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ResearchBlogging.org

The Japanese folktale can be found, among other places, in The Wise Old Woman/retold by Yoshiko Uchida; illustrated by Martin Springett. ISBN: 0689505825.

McComb, K., Shannon, G., Durant, S., Sayialel, K., Slotow, R., Poole, J., & Moss, C. (2011). Leadership in elephants: the adaptive value of age Proceedings of the Royal Society B: Biological Sciences, 278 (1722), 3270-3276 DOI: 10.1098/rspb.2011.0168.

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Analogical Reasoning in Animals

In today’s post, I’d like to explore some surprising recent findings about the abilities of animals in the area of analogical reasoning.

Reasoning by analogy is central to the way we think, enabling us to use familiar concepts to solve new problems. When a catastrophic event strikes Wall Street, economists inevitably point to analogous historical disruptions in their attempts to predict whether we’re facing long-term troubles or a quick recovery. When lawyers advocate on behalf of clients in new realms such as digital media, they often ground their arguments in principles that evolved centuries ago to protect real property interests. When scientists explain the motion of molecules and other phenomena that we cannot directly perceive, they frequently turn to concrete examples such as colliding billiard balls or streams of water.

On a more mundane level, analogical thinking underlies many of our idioms and permeates our everyday language. Think how lost you’d be if you were suddenly unable to understand phrases that explicitly or implicitly apply concepts from one context to events or actions in another. Conversations at work would confuse you (more than usual). Your boss’ suggestion that you take some time off to recharge your batteries would leave you scratching your head rather than looking for deals on tropical island vacations. You wouldn’t be able to follow political discussions (oh no!). You’d be the only one asking “oh my god, was it with guns or knives?” after hearing that one candidate outdueled another in a debate. You’d be the only one worrying about cannibalism after learning that the people were hungry for new leadership. You’d find sports to be newly upsetting, as you’d literally go into mourning after learning of your favorite team’s fatal missteps. (Ok, I take that back – nothing has changed here, especially for Boston Red Sox fans.)

Relational Matching Tests

One of the most common tests used to assess an individual’s ability to solve analogy problems is known as relational matching-to-sample or RMTS. In its classic form, RMTS involves first showing the subject a sample set consisting of two or more objects that are either identical (for example, two circles) or nonidentical (for example, a square and a circle). Sets containing identical objects are sometimes referred to as reflecting the “identity relation” and those containing nonidentical objects are said to reflect the “nonidentity relation.” Next the subject is shown two comparison sets containing novel objects, one embodying the identity relation (e.g., two triangles) and the other the nonidentity relation (e.g., a rectangle and a triangle). To succeed, the subject must choose the comparison set that matches the relationship demonstrated by sample set. For instance, the correct choice for a subject shown two circles in the sample would be the comparison set containing the two triangles, whereas the correct choice for the subject initially shown the square and the circle would be the comparison set containing the rectangle and the triangle.

RMTS is particularly well suited for testing the abilities of non-human animals, as it poses an analogy problem in a strictly visual manner, not relying in any way on linguistic skills. In essence, success requires the subject to not only make a “first order comparison” between same and different, but also to make a “second order comparison” by applying this underlying distinction to a novel environment. Many researchers consider this ability to lie at heart of analogical reasoning.

A “Profound Disparity”?

Until recently, studies have suggested that humans and a select few great apes stand far apart from all other animals in terms of analogical reasoning abilities. While many animals can successfully distinguish between same and different shapes or colors, they tend to struggle when it comes to making second order comparisons of the sort required by RMTS tasks. Since only humans and some chimpanzees, gorillas and orangutans have performed well at RMTS testing, researchers have proposed that a “profound disparity” exists between the analogical reasoning capacity of hominids and other animals.

For example, several studies have shown that some baboons and pigeons can learn to pass RMTS tests if they involve large-sample and comparison sets (e.g., comparisons involving 4 x 4 grids of 16 all identical and 16 all different objects), but that their performance rapidly deteriorates as the size of the grid decreases as well as when the distance between the objects in the grid increases. According to researchers, one reason why animals do better with larger sample sets may be that there’s a greater amount of variation or “entropy” between non-analogous grids in larger sample and comparison sets, which makes the task of distinguishing between potential answers easier.

Notwithstanding these prior findings, however, two studies published in the last few months now pose a challenge to the “profound disparity” concept, suggesting that a suitable testing environment can showcase robust analogical reasoning skills in non-apes.

Clever Capuchins

In the first study, which was published in PLoS ONE in August 2011, researchers led by Valentina Truppa and Elisabetta Visalberghi of the National Research Council in Rome, Italy, found that New World tufted capuchin monkeys (Cebus apella) were capable of solving RMTS tasks involving sample and comparison sets involving sets of as few as two objects.

What are all of those freaking squiggles in that diagram above my head? (image credit: Charlesjsharp)

The research team studied five capuchin monkeys, testing them over and over again on RMTS tasks involving varying numbers of icons. While the specific tests varied, the general approach was to start by giving the monkeys trials involving a relatively small pool of different icons and, only if and when a monkey achieved proficiency (as measured by percentages of correct answers) over the course of thousands of trials, to introduce novel icons for comparison. Also, in one of the experiments, if the monkey did not ultimately reach the proficiency threshold on a two-icon comparison test, “entropy” was increased and the monkey was given an easier four-icon test.

Ultimately, after a total of 21,888 trials (yes, that’s correct!) one of the five capuchins, Roberta, proved to be a real overachiever. As the researchers put it:

The current study demonstrates the acquisition of abstract concepts based on second-order relations by one capuchin monkey, Roberta. She was first successful with four-item stimuli and then with two-item stimuli, the latter being the most difficult condition previously thought to be mastered only by apes. Since her performance was robust across different types of stimuli and well above that of the other subjects, we can argue that relational analogies are very difficult for capuchins, but under specific circumstances not impossible.

Way to go, Roberta!

Bright Baboons

In a second study, published on September 20, 2011, in Psychological Science, a research team headed by Joël Fagot of the Centre National de la Recherche Scientifique at the Université de Provence reported that guinea baboons (Papio papio) can learn to perform surprisingly well at RMTS tasks … and then retain this ability over a 12-month period. In this study, 29 baboons with no language training and little or no experience with relational matching tests participated in various RMTS experiments involving geometric shape comparisons.

All this RMTS stuff gives me a headache (image: Animal Globe)

The first experiment consisted of classic RMTS trials, each involving a sample set made up of pairs of identical or nonidentical geometric shapes, and two comparison sets with new geometric shapes, with only one of the comparison sets matching the relationship demonstrated by the sample set. At first, the testing pairs were selected randomly from among 10 geometric shapes, but once a baboon had achieved an accuracy level of 80% or better in three consecutive sessions of 100 trials, new geometric shapes were introduced up to a maximum of 90 shapes by the end of the experiment. Six of the 29 baboons were able to make it to the 80% threshold level, and five were ultimately able to proceed through testing until they reached all 90 shapes.

The second experiment included changes designed to make the challenge more difficult: the geometric shapes were moved further apart and, perhaps more significantly, in half of the tests the “incorrect” comparison pair, rather than containing all new geometric shapes, actually contained one of the shapes from the sample pair. In other words, even though this comparison pair was incorrect from the standpoint of analogy testing, it contained a shape that was directly linked to the sample set, potentially confusing the baboon if it was focused on the similarity of the shapes rather than the conceptual relationship between the shapes.

In spite of the enhanced degree of difficulty, all five of the baboons who participated – the same baboons who had been successful in the first experiment – performed at above chance levels throughout the second experiment (although, not surprisingly, their performance tailed off somewhat in the trials where the incorrect response shared a shape with the sample set).

Finally, the research team retested the five successful baboons in accordance with the first experiment methodology after a one-year lapse during which the baboons had no practice at RMTS tasks. All five baboons reached the 80% success level far more quickly than they had the first time around, providing strong evidence that they had been able to retain their relational matching skills over this one-year period.

As with the capuchin monkeys, the baboons were not naturals at these tests – they went through thousands upon thousands of trials and only gradually acquired their relational-matching skills. Once again, though, the research strongly suggests that there is not a bright line “profound disparity” between the capabilities of hominids and those of other animals, and that other animals can demonstrate the cognitive foundation necessary for abstract analogical reasoning.

So, as in other areas, the more we explore the abilities of animals, the more we find that we have been wrong about what we thought were cognitive barriers. As we become more adept at designing experiments that are patiently conducted and thoughtfully tailored to the skills and natural adaptations of the specific animals we are studying (rather than the skills and adaptations of college undergraduates), we should continue to see the breakdown of additional barriers.

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ResearchBlogging.orgTruppa, V., Piano Mortari, E., Garofoli, D., Privitera, S., & Visalberghi, E. (2011). Same/Different Concept Learning by Capuchin Monkeys in Matching-to-Sample Tasks PLoS ONE, 6 (8) DOI: 10.1371/journal.pone.0023809

Fagot, J., & Thompson, R. (2011). Generalized Relational Matching by Guinea Baboons (Papio papio) in Two-by-Two-Item Analogy Problems Psychological Science, 22 (10), 1304-1309 DOI: 10.1177/0956797611422916

Converging with Canines: Are Humans and Dogs Evolving Together?

In our man-made world, it can feel like everything is converging all at once. Indistinguishable glass skyscrapers sprout up in cities all over the globe, near identical car models vent carbon dioxide into the air on different continents, and people around the world see their waistbands expand as they gulp down the same McFood. Global economies are more connected than ever, with natural disasters in Japan, sovereign debt issues in Europe, and rumors of Wall Street misdeeds shaking worldwide markets within minutes. Even the social media that deluge us with information seem like they’re growing more and more alike, as we now drown in unending streams of look-alike feeds, postings, messages and links from Twitter, Facebook, Google+ and others.

You may wonder whether the forces of convergence are a recent phenomenon, a product of human technology, or whether they may have deeper roots in the natural world. In fact, convergence can and does occur in the realm of biological evolution, albeit at a more comfortable pace. For example, “convergent evolution” occurs when different species independently evolve similar solutions to comparable evolutionary pressures. A classic example of this is the development of wings and the ability to fly by birds, bats and pterosaurs:

Diagram of wing morphology and/or and comparative network hub structure of Twitter, Facebook and Google+ (image credit: National Center for Science Education)

Consider also the independent evolution of sleek, torpedo-shaped bodies by fish, cetaceans and ichthyosaurs:

Sleek ocean swimmers (image credit: All About Reptiles)

Closer to home, scientists at the Max Planck Institute for Evolutionary Anthropology have concluded that we may be undergoing a process of cognitive convergent evolution with dogs based on our social relationships over thousands of years with these “best friends” of ours. In a paper published in Trends in Cognitive Sciences, Brian Hare and Michael Tomasello reviewed a large number of studies focused on canine, human, and non-human primate social and communicative skills and reached some interesting conclusions.

Proof of convergent canine-human evolution (source unknown)

They began their analysis by focusing on research showing how well domestic dogs do at interpreting human social and communicative behavior. For example, dogs excel at tests in which experimenters hide food in one of several opaque containers and then signal where it has been hidden by pointing, gazing, bowing or nodding, or placing markers in front of the target location. The dogs easily interpret this type of cue, passing tests such as these on the first attempt and performing correctly even when humans try to trick them by walking towards the wrong container while pointing in the opposite direction to the correct container.

Also, studies have shown that dogs are aware of what humans can see. For instance, if a human turns around during a game of fetch, the dog will almost invariably bring the ball back around the human and drop the ball in front of his face. Similarly, dogs have shown that they prefer to beg for food from humans whose eyes are visible than from ones whose eyes are covered with a blindfold or bucket, but are more likely to approach forbidden food when a human’s eyes are closed.

Indeed, dogs actually consistently outperform chimpanzees and other primates at these types of skills, even though, in areas of non-social cognitive performance, dogs do not do so well. For example, non-human great apes are much better at making inferences about the location of hidden food based on non-social cues (such as a tilted board that might be tipped up by hidden treats) and at tests that require them to achieve food rewards by, for example, reeling in food attached to strings.

With this in mind, Hare and Tomasello turned to whether domestic dogs’ specialized social skills are likely to be due to convergent cognitive evolution with humans or whether another explanation is more plausible.

First, they considered the possibility that dogs learn to recognize human social cues based on their experiences growing up in human households. They found, however, that studies show that even puppies as young as nine weeks old are adept at solving problems using human pointing and gaze cues, and that puppies raised without much exposure to humans are equally skilled at interpreting these cues.

Then, they considered whether domestic dogs may have simply inherited their social skills based on their common ancestry with wolves, since wolves are, after all, pack hunters who need to be able to follow complex social interactions with other wolves and with prey. However, although wolves are generally equal to or better than domestic dogs at memory tests and tasks involving general problem-solving abilities, wolves (even those raised by humans) are simply unable to match the performance of dogs at spontaneously using human social cues to solve problems.

Next, the researchers sought evidence for the evolution of social skills in dogs through their long-term relationship with humans. They looked at a population of domesticated foxes, where the selection for breeding had been based solely on the tendency of individual foxes to be non-aggressive and fearless around humans. Interestingly, these foxes were just as adept as dogs in using and interpreting human social cues, and far better than a population of control foxes that had been bread randomly with respect to their attitude towards humans.

Based on all of these comparative findings, Hare and Tomasello concluded that the best explanation for dogs’ specialized social skills is that they evolved as a consequence of dogs having been domesticating by humans, representing a case of convergent cognitive evolution. Interestingly, Hare and Tomasello went further and, based on their review of the research on domesticated foxes, concluded that the evolution of specialized social skills in domesticated dogs may actually have been an incidental byproduct of an initial decision to select based solely on nonaggression (as opposed to social intelligence).

Finally, turning to primate evolution, Hare and Tomasello speculated that a similar process may have contributed to differences between human and chimpanzee social skills. Under what they refer to as the “emotional reactivity” hypothesis, they predicted that differences in temperament between humans and other primates may help explain some of humans’ extraordinary social cognitive abilities. They point to studies showing that chimpanzees’ willingness to cooperate with each other can often be limited by lack of social tolerance for one another resulting from fear and/or aggression, and contrast this to a more socially tolerant temperament that may ultimately have enabled our hominid ancestors to develop flexible forms of cooperation and communication. In other words, humans underwent a form of self-domestication leading to greater social abilities, thereby convergently evolving with our canine companions who were undergoing the same process.

I’m not sure I entirely buy the notion that we humans are so exceptionally tolerant, but I have noticed that you’ve started to look a bit like your dog. In a future post, we may look at whether we may also be evolving to be more like members of the cat family:

Which one is the lion? (source unknown)

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ResearchBlogging.orgHare, B., & Tomasello, M. (2005). Human-like social skills in dogs? Trends in Cognitive Sciences, 9 (9), 439-444 DOI: 10.1016/j.tics.2005.07.003

Grief in Animals

I’ve been thinking about grief lately. It can be so overpowering – the dull ache of emptiness, the stabbing pain of loss, and the prism of sadness that transforms the bright colors of everyday life into a harsh and alien landscape. Consumed by grief, we are alone; yet somehow our solitary suffering can end up strengthening the bonds we have with others we know and love.

I’ve also been thinking about grief in animals, and what we know about it. When our cat Puggsley died, our younger Siamese, Moose, felt the full impact of the loss. The two had always been close, perhaps tied together by their mutual skepticism over Wednesday, our third cat and official people-pleaser. Moose and Puggsley were constant companions, playmates, napping buddies, and a rather frightening pair of mischief makers. When Puggsley became old and frail, he would curl up stiffly by the fireplace, and Moose would bed down near him. At the very end, Moose was right there, tenderly licking Puggsley as he was overcome by a seizure. And after he was gone, she mourned – she was lost without her friend, and had little appetite or energy for weeks. She never bedded down by the fireplace again. How do I know this was grief? Well, it was obvious; I just know.

Puggsley and Moose

But what do we really know about grief in animals – that is, in a scientific sense? Not particularly much, it turns out.

We are (mostly) beyond the era in which animals were considered thoughtless automatons, incapable of feeling pain and other emotions. Still, there have been relatively few formal studies of how animals experience grief.

In a way, this isn’t so surprising. For one, opportunities to systematically observe grieving behavior in the wild are rare and, if you think about it, it’s difficult to design ethical studies intended to cause social animals to grieve in captive settings. Also, what specifically do you test for and how do you quantify and evaluate an inherently subjective experience like grief? It’s tough enough to evaluate this sort of thing in humans, who can respond to questionnaires and use language to express their emotions….

As a result, most the scientific literature about grief in animals is anecdotal or observational in nature, and in many of these accounts it’s clear that otherwise objective researchers have struggled to come up with scientific ways of reporting what, in the end, are their own reactions, what they just know.

Although the record is sparse everywhere, there have been some recent papers on grief in primates. Brian Switek, who writes the Laelaps blog for Wired Magazine, has written a terrific piece on this research in his “What Death Means to Primates” posting (I strongly encourage you to check out Laelaps; it’s one of the best blogs out there on paleontology, evolution, and the history of science).

As Brian recounts in detail, studies have documented chimpanzee and other primate mothers who have continued to carry dead infants, sometimes for weeks and even to the point of mummification. In one of the studies1, researchers described two chimpanzee mothers (Jire and Vuavua) in Bossou, Guinea, who carried their dead babies (aged 1.2 years old and 2.6 years old, respectively) after they had died in a respiratory epidemic, grooming them regularly, chasing away flies, and carrying them during all travel. The researchers pondered:

An obvious and fascinating question concerns the extent to which Jire and Vuavua “understood” that their offspring were dead. In many ways they treated the corpses as live infants, particularly in the initial phase following death. Nevertheless they may well have been aware that the bodies were inanimate, consequently adopting carrying techniques never normally employed with healthy young (although mothers of handicapped young have also been known to respond appropriately).

In another study2, James Anderson, Alasdair Gillies and Louise Lock reported on the peaceful death of an older chimpanzee, Pansy, who lived in a safari park. They videotaped the reactions of Pansy’s companions and observed a number of behaviors that they found to be comparable to human bereavement. The degree to which the researchers sought out human counterparts to the chimps’ behavior is evident from the following description in their paper:

During Pansy’s final days the others were quiet and attentive to her, and they altered their nesting arrangements (respect, care, anticipatory grief). When Pansy died they appeared to test for signs of life by closely inspecting her mouth and manipulating her limbs (test for pulse or breath). Shortly afterwards, the adult male attacked the dead female, possibly attempting to rouse her (attempted resuscitation); attacks may also have expressed anger or frustration (denial, feelings of anger towards the deceased). The adult daughter remained near the mother’s corpse throughout the night (night-time vigil), while Blossom groomed Chippy for an extraordinary amount of time (consolation, social support). All three chimpanzees changed posture frequently during the night (disturbed sleep). They removed straw from Pansy’s body the next morning (cleaning the body). For weeks post-death, the survivors remained lethargic and quiet, and they ate less than normal (grief, mourning). They avoided sleeping on the deathbed platform for several days (leaving objects or places associated with the deceased untouched).

With this focus, it’s not surprising that they concluded by proposing that “chimpanzees’ awareness of death has been underestimated.”

Also, more anecdotally, many were moved by the apparent grief captured in this poignant National Geographic photo of chimpanzees at a rehabilitation center peering at the lifeless body of Dorothy, their long-time companion, being taken to her burial:

Chimpanzee burial (National Geographic, photo: Monica Szczupider)

There has also been some research into the behavior of elephants towards the dead and dying. In one study3, Iain Douglas-Hamilton, Shivani Bhalla, George Wittemyer and Fritz Vollrath reported on the death of Eleanor, a matriarch elephant in the Samburu National Reserve in Kenya. They were able to use GPS technology to track the movements of elephants in Eleanor’s family and in other families as they reacted to her collapse and subsequent death. The researchers found that Eleanor was visited frequently by both related and unrelated elephants, concluding:

Combined with earlier work and the data of other scientists it leads to the conclusion that elephants have a generalized response to suffering and death of conspecifics and that this is not restricted to kin. It is an example of how elephants and humans may share emotions, such as compassion, and have an awareness and interest about death.

Grace visiting Eleanor's body (photo: Douglas-Hamilton, et al)

In another paper4, Karen McComb, Lucy Baker and Cynthia Moss described experiments in which they assessed elephants’ strong interest in and sometimes dramatic reactions to elephant bones and tusks. After systematically presenting elephants in Amboseli National Park in Kenya with different combinations of elephant and other animal skulls, ivory and pieces of wood, the researchers found that the elephants were significantly more interested in elephant skulls and tusks than they were in the skulls of other animals or in the wood, but that they did not demonstrate a special affinity to the skulls or ivory of deceased relatives. The following video provides a nice glimpse into the way in which elephants seem to be fascinated by elephant bones and tusks:

Several reports have also documented cetaceans reacting with apparent grief. In one report5, for example, Mark Simmonds described an incident in which two male orcas appeared to grieve over the death of a female orca thought to be their mother. For years, the two males had spent all their time swimming with this female. After her death, the males were seen swimming together but apart from all other orcas for a day or two, repeatedly visiting the places that their mother had passed in her last few days. In another instance, Robin Baird of the Cascadia Research Collective reported seeing two orcas, a mother and adult son, swimming with a dead calf in the Puget Sound, with the mother balancing the calf on her rostrum or carrying it on top of her head and occasionally lifting it out of the water, and both adults diving deep to recover the baby when it began sinking.

Dolphin and calf (Tethys Research)

Scientists at the Tethys Research Institute related a similar occurrence off the coast of Greece, where a mother bottlenose dolphin was seen interacting with a dead newborn calf. Their description vividly underscores the difficulties in evaluating these sorts of situations from a scientific perspective:

Whilst researchers must avoid being driven by their own feelings and make arbitrary interpretations, in this case it was quite clear that the mother was mourning. She seemed to be unable to accept the death, and was behaving as if there was any hope of rescuing her calf. She lifted the little corpse above the surface, in an apparent late attempt to let the calf breath. She also pushed the calf underwater, perhaps hoping that the baby could dive again. These behaviours were repeated over and over again, and sometimes frantically, during two days of observation.

The mother did never separate from her calf. From the boat, researchers and volunteers could hear heartbreaking cries while she touched her offspring with the rostrum and pectoral fins. Witnessing such desperate behaviour was a shocking experience for those on board the research boat.

Finally, Marc Bekoff (he of the Yellow Snow fame) has written an eloquent article that includes many additional anecdotes regarding animal grief in his Psychology Today column.

Ultimately, there is much we will never be able to understand regarding how animals experience the world. We can trace commonalities between human and other animal brain structures and neural pathways associated with emotional experiences, and we can try to add more systematic observations to our collection of behavioral anecdotes, but in some fundamental ways the animal mind (and, for that matter, the mind of other humans) will always be cloaked in private experience, inaccessible to us. Moreover, as some of the accounts in this post have illustrated, our attempts at understanding animal emotions are inevitably colored by our own human experiences. We can know human grief, but how can we understand what it means to experience chimp grief, or elephant grief, or orca grief?

Nevertheless, just because we cannot fully comprehend what we see in other animals, that does not mean that grief in animals does not exist or that animals cannot lead rich emotional lives. Indeed, what we do see is a pattern that makes it increasing clear that death can impact other animals profoundly.

How do I know this? Just ask Moose, Puggsley or Wednesday – I just know.

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ResearchBlogging.org1Biro, D., Humle, T., Koops, K., Sousa, C., Hayashi, M., & Matsuzawa, T. (2010). Chimpanzee mothers at Bossou, Guinea carry the mummified remains of their dead infants Current Biology, 20 (8) DOI: 10.1016/j.cub.2010.02.031.

2Anderson, J., Gillies, A., & Lock, L. (2010). Pan thanatology Current Biology, 20 (8) DOI: 10.1016/j.cub.2010.02.010.

3Douglas-Hamilton, I., Bhalla, S., Wittemyer, G., & Vollrath, F. (2006). Behavioural reactions of elephants towards a dying and deceased matriarch Applied Animal Behaviour Science, 100 (1-2), 87-102 DOI: 10.1016/j.applanim.2006.04.014.

4McComb, K., Baker, L., & Moss, C. (2006). African elephants show high levels of interest in the skulls and ivory of their own species Biology Letters, 2 (1), 26-28 DOI: 10.1098/rsbl.2005.0400.

5Simmonds, M. (2006). Into the brains of whales Applied Animal Behaviour Science, 100 (1-2), 103-116 DOI: 10.1016/j.applanim.2006.04.015.

Multi-Modal Monkey Memory

Recognizing someone you know is actually not a simple cognitive task – it requires you interpret the information you’re currently receiving through your senses, and then link back to a previously-formed conceptual representation you have of the individual in question. It’s especially difficult if you are acting cross-modally, for example matching someone’s voice to a photograph or vice versa.

Oh yeah, I remember him. He's the one with the high squeaky voice, isn't he? (photo credit: Joe Kegley)

Recently, two separate studies have shown that rhesus macaque monkeys (Macaca mulatta) are quite up to this challenge, reflecting that they possess a considerable degree of social memory and engage in complex conceptual thinking about other individuals.

French Pictures

In the first study1, published earlier this year in Proceedings of the National Academy of Sciences, a French research team headed by Julian Sliwa of the University of Lyon confirmed that rhesus macaques are able to spontaneously match the faces of known macaques and humans to their voices.

In their experiments, the research team gave six macaques a large number of tests in which they played short voice samples of known individuals (coos and grunts for other macaques, short French sentences and phrases for humans) and then measured how long the macaques spontaneously looked at cropped photographs of two known faces, only one of which matched the voice they had heard. The researchers statistically analyzed whether the macaques spent more time looking at specific photos after hearing the matching voice than they did after hearing a different voice, and found that the macaques did indeed stare significantly longer at a photo – whether of another macaque or a human – if the matching voice had been played first.

In reviewing individual performance, the researchers observed that five of six of the macaques displayed this effect overall, and that a greater number were better at recognizing photos that matched human voices than ones matching the voices of fellow macaques (the researchers noted that they were surprised at this finding, but pointed out that perhaps the explanation was that there were more useful auditory cues in the human speech samples than there were in the monkey coo vocalizations). Finally, the researchers found that five of the six monkeys showed preferences for specific faces, spending an especially long time looking at matching” photos of certain individuals – often a “neighbor” monkey or the researcher who was their main caregiver.

The researchers concluded that rhesus macaques can recognize individuals, linking together abbreviated visual and auditory perceptual cues (small, two-dimensional photos and short sound samples) to spontaneously identify other macaques and socially-relevant humans, and even to reflect the preference biases they have towards specific individuals.

At the Movies

The second study2, published last week in PLOS ONE, extended the findings to show that rhesus macaques can also recognize photos of other macaques whom they had seen during video clips, an additional challenge because specific features can be harder to identify in dynamic movies than in still images.

In this study, researchers led by Ikuma Adachi of the Yerkes National Primate Research Center began by training five macaques to watch brief silent video clips of familiar individuals before identifying which of five randomly placed photos represented the individual in the video. At first the macaques were allowed to continue to look at the last frame of the video before having to choose the correct photo, but in a second phase of the experiment the screen went black after the video was played, and the monkeys had to choose the correct photo after a time lag.

In each case the macaques became proficient at the task, even performing well after seeing videos taken from a novel perspective that was substantially different than the view in the training videos. Thus, their performance suggested that they were able to recognize specific features of known individuals as they appeared in dynamically-changing scenes in a range of videos, and then extract that information to identify those individuals later on in still images.

Next, the researchers repeated the testing, but this time they tweaked the conditions by playing a brief vocalization right after showing the last frame of the some of the videos – either a vocalization of the macaque in the video (the “congruent condition”) or of a different macaque (the “incongruent condition”). Only two of the macaques participated in this testing, as apparently the other three weren’t comfortable with working in the sound isolation booth necessary for this phase.

The researchers found that the macaques, who had never been trained to use vocalizations to guide their test responses, continued to be good at choosing the “correct” photo, but that when they made errors, they were statistically more likely than chance to pick the image of the vocalizing monkey, rather than the one in the video.

In other words, hearing the vocalizations systematically biased the macaques’ choice behavior, indicating that the voices may have activated visual representations of the vocalizing monkeys that occasionally superseded the impact of what had been seen in the video. Again, the macaques were demonstrating how they processed the information they used to recognize information cross-modally.

So, clearly “see no evil” is linked to “hear no evil” – perhaps we’ll see how “speak no evil” fits into the picture in a later post.

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ResearchBlogging.org

1Sliwa J, Duhamel JR, Pascalis O, & Wirth S (2011). Spontaneous voice-face identity matching by rhesus monkeys for familiar conspecifics and humans. Proceedings of the National Academy of Sciences of the United States of America, 108 (4), 1735-40 PMID: 21220340.

2Adachi, I., & Hampton, R. (2011). Rhesus Monkeys See Who They Hear: Spontaneous Cross-Modal Memory for Familiar Conspecifics PLoS ONE, 6 (8) DOI: 10.1371/journal.pone.0023345.

Grandmothers and Menopause in Cetaceans and Humans

As single income families become rarer and aging baby boomers begin to play a greater role in caring for their grandchildren, people have increasingly come to appreciate how much help a doting grandmother can provide. In fact, interest in the helpful role played by the elderly has given rise to the so-called grandmother hypothesis, which posits that women have evolved to live well past their reproductive years because, free from the costs of childbearing, they are able to invest more time into benefiting their grandchildren and other younger family members, raising the odds that their genes will be carried on to future generations.1 While the strength of the evidence for the grandmother hypothesis is still being debated2, it’s certainly got some intuitive appeal (especially, perhaps, to harried young parents).

What’s also quite fascinating is that the long post-reproductive life of human females – up to a third of a woman’s lifespan or more – is extremely rare: menopause appears to be unique to humans and (somewhat controversially) certain other great apes, as well as to certain toothed whales, including short-finned pilot whales and killer whales. (It’s possible that other species of cetacean may undergo menopause, but this hasn’t been established yet; also, more to come about elderly elephant matriarchs in a later post…)

To grandmother's house I go! (Photo: © Alice MacKay, Cascadia Research)

So, why is post-reproductive life is so rare? If the grandmother hypothesis applies to great apes and toothed whales, why isn’t it at work with other long-lived animals who live in socially-cooperative societies? Also, if evolution favors post-reproductive life because it provides distinct social advantages, why did menopause evolve in humans and toothed whales, given the very different social structures of humans and whales?

A fascinating study published last year in Proceedings of the Royal Society B3 by Rufus Johnstone of the University of Cambridge and Michael Cant of the University of Exeter may offer plausible answers to these questions.

In a nutshell, they found that, although humans, pilot whales and killer whales have quite different social systems, in each case older females become, on average, more genetically related to those with whom they associate. By contrast, in most other long-lived complex mammal societies, older females become increasingly less related to those in their local groups as they age.

Did grandma pinch you on the cheek too? (photo credit: NOAA)

The researchers began by developing a mathematical model that would allow them to draw general conclusions about age-related changes in the genetic relatedness of long-lived social animals as individual group members disperse, die and are replaced over time. (For those interested in such things, they based their approach on the “infinite island” model that is commonly used in considering the process of gene flow among a set of subpopulations.)

With their model in hand, the researchers analyzed three relevant social scenarios:

  1. Males Move On. In the large majority of social animal societies, males tend to move on as they mature, ultimately mating with unrelated females they find within new social groups. In this type of society, the researchers’ model determined that, over time, an older female will become less related to her group mates as she ages. She starts out in a highly related group that includes her father, but over time her older male relatives die, and her sons, and the sons of her relatives, leave the group and are replaced by unrelated males from other groups. Her average genetic relationship to the females in the group doesn’t change much, but since her relatedness to local males declines, overall her genetic connection to the group lessens as she gets older.
  2. Females Move On. Conversely, evidence suggests that during the course of human evolution, women were the ones that were more likely to move on to start families in new environments. (In support of this proposition, Johnstone and Cant cite the behavior of other great apes, human DNA variation patterns, and social patterns among human forager societies, evidence they concede is “far from conclusive.”) In this type of society, where males stay at home and females disperse, an older female tends to become more related to her fellow group members over time. She begins her reproductive life in new surroundings where she has few genetic ties to those around her, but as she produces sons who are likely to remain in the group, her relatedness to local males builds up over time. Again, because the degree of her relatedness to other females stays fairly constant – she starts out with little relation to the females in her new group and this doesn’t change much as her daughters leave and are replaced by new unrelated females – her overall genetic connection to the group increases as she ages.
  3. Males and Females Stay Put, But Mating Occurs Between Different Groups. In the resident killer whale and pilot whale societies studied, males and females stay with their natal groups for life, but mating occurs non-locally, that is, between females and males from other groups. In this final scenario, even though the social structure is quite different from “female moves on” societies, the results are the same: an older female tends to become more related to her fellow group members over time. A female begins her reproductive life separate from her father and her paternal relatives (who belong to a different group), but as she has male offspring her relatedness to males within her group grows over time. Once again, her relatedness to other females stays more or less constant, meaning that her overall genetic affinity with her group increases as she grows old.

Thus for human and certain whale societies, in contrast to most other social animal groupings, a female’s relatedness to her group increases as she becomes older.

Johnstone and Natal next considered the fitness costs of reproduction. They noted that having children imposes costs on other breeders within one’s group due to increased competition for food, resources and mating opportunities, whereas cessation of reproduction confers a benefit, due to a corresponding reduction in competition. Then, using a using a statistical model involving an “inclusive fitness” approach to generate quantitative results for the three scenarios described above, they reached a not-surprising conclusion: in scenario 1 (males move on), it is less advantageous for older females to “help” younger generations by stopping their own breeding, whereas in scenarios 2 and 3 (the human and toothed whale scenarios), non-breeding “help” is favored by evolution, as it confers advantages on a younger generation that is progressively more related to the older helper.

So there you have it. Does Johnstone and Natal’s analysis sound plausible? It certainly offers a neat way of finding an underlying similarity in great ape and whale societies that may explain menopause and support the grandmother hypothesis in these very distinct groups.

No wonder cetaceans often look like they’re grinning – they’ve been spoiled by their grandmothers!

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ResearchBlogging.org1See, e.g., Lahdenperä, M., Lummaa, V., Helle, S., Tremblay, M., & Russell, A. (2004). Fitness benefits of prolonged post-reproductive lifespan in women Nature, 428 (6979), 178-181 DOI: 10.1038/nature02367; Shanley, D., Sear, R., Mace, R., & Kirkwood, T. (2007). Testing evolutionary theories of menopause Proceedings of the Royal Society B: Biological Sciences, 274 (1628), 2943-2949 DOI: 10.1098/rspb.2007.1028.

2See, e.g., Kachel, A., Premo, L., & Hublin, J. (2010). Grandmothering and natural selection Proceedings of the Royal Society B: Biological Sciences, 278 (1704), 384-391 DOI: 10.1098/rspb.2010.1247.

3Johnstone, R., & Cant, M. (2010). The evolution of menopause in cetaceans and humans: the role of demography Proceedings of the Royal Society B: Biological Sciences, 277 (1701), 3765-3771 DOI: 10.1098/rspb.2010.0988.

Elephant Insight

With each passing week, it seems like we’re finding out more and more about how smart elephants are. Now, in addition to their other cognitive abilities, it turns out that elephants can have “aha!” moments of insight as they face puzzling dilemmas. [No, not a-ha as in 1980s synth-pop from Norway; if you’re looking for an early MTV a-ha moment, you should probably go here!]

Elephants have the largest brains and the greatest volume of cerebral cortex of all terrestrial mammals. They live in elaborate matriarchal societies that include long-lasting relationships, close family bonds, and complex social groupings that change over time. They squabble and negotiate with each other over travel directions; they flirt, show empathy towards one another and solve problems cooperatively. They are one of the very few animals that can recognize themselves in mirrors (more about self-recognition testing here and here). True to their reputations, they have terrific memories, are adept at making and using tools, are logical thinkers, and even appear to mourn their dead in a “ceremonial” manner suggesting they may have a real awareness of the separate lives and experiences of other elephants.

Until now, however, on the few occasions when elephants have been tested for insightful problem solving abilities, they have been performed poorly. In these previous tests, the elephants failed to use their trunks in order to gain access to food treats that had been placed just beyond reach (for example, by using a stick grasped in the trunk to reach out for the food, or by pulling on a retractable cord with their trunks in order to reel in the food reward).

In a paper just published online on August 18th in PLoS ONE, a research team led by Preston Foerder and Diana Reiss of the City University of New York reported on its own revelation that led to a breakthrough in tests for elephant problem-solving insight. The researchers surmised that the problem with prior testing was not that elephants were incapable of insight, but rather that the tests had called for the elephants to act in ways that undermined their ability to use their trunks as effective sense organs during the task:

We believe that the problem in previous studies has been in treating the elephant trunk as a grasping appendage analogous to a primate hand. Although the trunk is a highly manipulable appendage, in food foraging its function as a sensory organ may take precedence. The elephant has an extraordinary sense of smell, and the tip of the trunk is as highly enervated as a human fingertip…. When a stick is held in the trunk, the tip is curled backwards and may be closed, prohibiting olfactory and tactile feedback…. We posit that previous failures to observe insightful problem solving in elephants is not indicative of a lack of cognitive ability but rather is due to the reliance on problem solving tasks that precluded the use of the trunk as a sense organ.

To address this issue, the researchers set up a series of experiments designed to allow elephants to keep their trunks free while facing problem-solving challenges. They tested three Asian elephants (Elephas maximus), two adult females and a 7-year-old juvenile male, at the Smithsonian National Zoo in Washington, DC, with the juvenile male, Kandula, soon emerging as the rock star problem-solver.

In the first experiment, the researchers dangled enticing fruit rewards from a cable they had placed across the elephant yard, including from positions that were just beyond trunk-reach. After leaving a large plastic cube and some other objects in the yard, they let Kandula into the yard for sessions to see whether he would figure out how to obtain the dangling food reward. While Kandula had previously played with the cube as an enrichment toy, he had no prior training in pushing large objects or in standing on them to reach for things.

During an initial six sessions, each lasting 20 some minutes, Kandula showed interest in the food dangling above his reach, played with the cube, moved it on several occasions, and once even stood on it briefly, but never tried to reach out for anything while standing on the cube.

Then, during the seventh session, Kandula suddenly had his moment of epiphany: he rolled the cube into position beneath the hanging food, stood on the cube with his front two feet, stretched out his trunk, and grabbed his prize.

Kandula - Insightful and Now Less Hungry Elephant

From then on, Kandula was off to the races. In the next session, he not only rolled the cube over and stood on it to reach the fruit again, he also started using the cube as a tool to reach other objects: e.g., standing on it to explore the inside of an enrichment object and, after rolling it to the edge of the yard, using it as a platform to reach for blossoms on an overhanging tree branch.

Moreover, Kandula showed he was able to apply his insight to new situations. For example, in a second experiment, the researchers used the same general setup, but began moving the cube around from place to place, including behind fences and in locations that Kandula couldn’t see as he entered the yard. In each case, Kandula found the cube and rolled it over to capture his food reward. Here’s a video of Kandula retrieving the cube from behind a fence:

Next, the researchers replaced the cube with a large tractor tire – in three of four sessions Kandula used the tire as a tool, rolling it to the proper place, and then standing on it to obtain the food reward.

In a final experiment, the researchers replaced the cube and the tire with a variety of other objects, including large plastic balls, discs, cones, a barrel lid and three cutting boards that would have to be stacked to form a platform for Kandula to reach the food. While Kandula didn’t stack all three boards (he did stack two, though), he experimented with various approaches such as standing with one foot on separate objects. Ultimately, he reached the food by standing on a plastic ball, a solution that surprised the researchers since he had never placed his weight on a similarly unstable platform before.

So, to summarize, Kandula demonstrated sudden insight – using a tool to solve a problem in a novel and spontaneous fashion, without evidence of prior trial and error learning. Further, he showed that he could repeat, transfer and extend his technique in subsequent sessions.

If you’re an elephant, please feel free to give yourself a pat on the back. Job well done!

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1Foerder, P., Galloway, M., Barthel, T., Moore, D., & Reiss, D. (2011). Insightful Problem Solving in an Asian Elephant PLoS ONE, 6 (8) DOI: 10.1371/journal.pone.0023251.

The “Yellow Snow” Test for Self-Recognition

The Mirror Self-Recognition Test

The mirror self-recognition (MSR) test has long been used to assess whether an animal is self-aware, whether it has a sense of self. In the classic version of the test, a colored mark is placed on an animal’s body in such a way that it can only be seen in a mirror. To pass the test, the animal must spontaneously use the mirror to detect the mark and then scratch or otherwise direct activity toward it, thereby indicating recognition of the image in the mirror as itself and not some other animal.

Not only is self-recognition considered to be an indication of higher cognitive functioning, but it has also been seen as a potential springboard to even more sophisticated abilities, such as being able to attribute mental states to other individuals (sometimes referred to as “theory of mind”).

To date, only a relatively few animals have passed the MSR test, including certain primates, dolphins, elephants, and, as we saw in a prior post, magpies.

But is the test itself biased? We humans rely heavily on our eyesight and may naturally – anthropocentrically – have settled on a test that is based on visual interpretation.

What about animals who rely more on their sense of smell – dogs, for instance? Well, Marc Bekoff, Professor Emeritus of Ecology and Evolutionary Biology at the University of Colorado, Boulder, wondered about this too.

The Yellow Snow Test

Over a five year period, Bekoff performed a study1 in which he diligently tracked the behavior of his own dog, Jethro, when Jethro encountered clumps of snow saturated with his own and other dogs’ urine (“yellow snow”) while walking freely along a bicycle path in Colorado on winter mornings.

Snow pile, snow pile, on the ground, who’s the finest smelling hound? (photo: Walter Jeffries)

Bekoff would wait until Jethro (a neutered male German Shepherd and Rottweiler mix) or other known female and male dogs urinated on snow, and then scoop up the clump of yellow snow as soon as Jethro was elsewhere and did not see him pick it up or move it (Bekoff used clean gloves each time and took other precautions to minimize odor and visual cues). Bekoff then moved the yellow snow varying distances down the path so that Jethro would run across the displaced urine: (i) within about 10 seconds, (ii) between 10-120 seconds later, or (iii) between 120-300 seconds later. After Jethro arrived, Bekoff recorded how long he sniffed at the yellow snow, whether he urinated over it using the typical male raised-leg posture, and whether urination immediately followed the sniffing (“scent marking”).

After compiling and statistically analyzing the data, Bekoff found that Jethro paid significantly less attention to his own displaced urine than he did to the displaced urine of other dogs. For example, when Jethro encountered the yellow snow within 10 seconds, he sniffed for longer than 3 seconds only about 10% of the time when it was his own urine, compared to over 80% of the time when it was other dogs’ urine. (Jethro did tend to have longer sniffs at his own urine when he arrived after more than 10 seconds, but in all scenarios he still sniffed significantly longer at the other dogs’ urine.) Likewise, he very rarely urinated over or scent-marked his own yellow snow, but frequently did so with the yellow snow of other dogs, particularly other males.

The following table summarizes the data collected (note that the reference to “120-150s” in the Arrives column appears to be erroneous, and should instead read “120-300s”):

In sum, Jethro’s behavior clearly demonstrates that he was able to discriminate the scent of his own urine from that of other dogs. Of course this is just one set of tests on one dog, but would it surprise anyone if other dogs showed similar abilities?

Is there a fundamental difference between an animal recognizing its own image in a mirror and one recognizing its own scent in yellow snow? There certainly are different cognitive process involved (Bekoff himself has suggested that the yellow snow test may be more indicative of a sense of “mine-ness” in dogs than of a sense of “I-ness”2).

At a minimum, though, the yellow snow test stands as a useful warning that we humans need to be careful not to make quick judgments about animal intelligence or cognitive capacity (or lack thereof) based on tests that are well-suited to humans, but that fail to match the skills and abilities of the particular animal.

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1Bekoff, M. (2001). Observations of scent-marking and discriminating self from others by a domestic dog (Canis familiaris): tales of displaced yellow snow Behavioural Processes, 55 (2), 75-79 DOI: 10.1016/S0376-6357(01)00142-5.

2Bekoff, M. Considering Animals—Not “Higher” Primates. Zygon 38, 229-245 (2003).

Be Kind to Cattle

The AnimalWise Soapbox

In a more ideal world, cattle would be free to lead lives consistent with their ancestry as nomadic grazers covering wide ranges. Of course, this isn’t a perfect world, particularly for the cows and other farmyard animals whose entire existence we have repurposed into the provision of meat and dairy products.

Without wading too deeply into the morass of moral issues raised by how we humans have transformed the environment and put other animals to work to serve our needs, it’s pretty clear that we have assumed a responsibility for the well-being of these animals who depend on us for everything.

Now, jumping down from the soapbox, what’s interesting is that, even if we were to disavow any ethical obligation to our bovine helpers, research continues to underscore how much it is in our own selfish interest to treat them with kindness and care.

A Cow by Any Other Name…

For example, one recent study1 that enjoyed some popular press attention found that named cows were better milk providers. That’s right, cows with names.

Uh oh, here comes what's-his-name...

In this study, researchers led by Catherine Bertenshaw and Peter Rowlinson of Newcastle University sent a detailed survey to every fourth dairy farm in England and Wales (1,000 in total), asking, farmers a number of questions regarding their attitudes toward cattle, how they managed dairy herds, and their perceptions of cows’ emotional and cognitive capacities. The response rate was 56% (52% after weeding out respondents who had recently ceased farming), with 90% coming from experienced stock managers who had worked with cattle for more than 15 years.

As noted above, cows don’t appear to enjoy toiling away in obscurity. On 46% of the surveyed farms, cows are called by name, and these cows produced an average of 258 liters more of milk per 10 month lactation period than did their anonymous peers (7938 liters versus 7680 liters). Moreover, on farms where the stock manager thought it important to know every individual animal, heifers had a 197 liter higher average milk yield over their first lactation than on farms where the manager thought it wasn’t important (6931 liters versus 6734 liters).

Does this mean that cows recognize their own names and appreciate it when they hear themselves being singled out?

While this is possible, the more likely explanation is that farmers who name and individually recognize dairy cows are more likely to treat them well. Bertenshaw and Rowlinson cite previous research finding attitude to be a reliable predictor of a person’s behavior around animals and that those having a positive attitude towards cows are “likely to handle animals patiently, to believe that regular positive contact is important, and to show positive behaviors towards the cows.”

Overall, the survey results indicate that – at least from the farmers’ perspective – there is a relatively positive relationship between dairy cows and stock persons on UK farms. Ninety percent of the respondents thought that cows had “feelings,” only 21% believed that dairy cattle were fearful of humans, and 78% thought cows were intelligent. (It would be interesting to see what percent think that their human coworkers were intelligent.) Also, on a somewhat reassuring note, 44% gave “love of cows” as a reason why they chose to work with cows.

Obviously, this is a subjective survey from one viewpoint (no word on when the cows will be receiving their questionnaires), but it provides important insight into the importance of our nurturing our relationships with other animals … and lessons that will serve us well when the Revolution comes (hilarious Dana Lyons video below):

♫  ♫  We will fight for bovine freedom, and hold our large heads high!   ♪  ♫  ♪

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1Bertenshaw, C., & Rowlinson, P. (2009). Exploring Stock Managers’ Perceptions of the Human–Animal Relationship on Dairy Farms and an Association with Milk Production Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals, 22 (1), 59-69 DOI: 10.2752/175303708X390473.

Pantomiming Primates

When considering language abilities in non-human animals, it pays to keep in mind that spoken words are not the only path to sophisticated communication. For example, while great apes like chimpanzees and orangutans may be limited in their ability to adapt their vocalizations to human speech, they are able to control their hand movements very well, and can engage in extremely expressive and effective gesturing behavior.

In a thought-provoking study first published online last year and now appearing in the August 23, 2011 issue of Biology Letters1, two Canadian researchers, Anne Russon of Glendon College and Kristin Andrews of York University, reported on their extensive review of data regarding instances in which orangutans in Borneo have used “pantomime” to communicate with their target audiences.

What part of "give me more food" don't you understand? (photo credit: Tom Low)

Russon and Andrews mined 20 years’ data that had been collected during systematic observational studies on the behavior of ex-captive orangutans as they underwent rehabilitation and were living free or semi-free lives in the forest. After reviewing original field notes and videos covering over 7,000 hours of observation, they identified 18 salient pantomime cases (14 addressed to humans and four to other orangutans) in which orangutans physically acted out messages in order to communicate specific goals.

In most of the cases, the orangutans used pantomime to provide additional or better information after an initial attempt at communication had failed – for example, by being more specific about an action, item or tool requested; by offering better tools for a requested task after a previous tool had been ignored; by pretending to be unable to perform a task after a request for help had been ignored; or by clarifying friendly intent after non-aggressive approaches had been refused.

A few specific examples will help to illustrate how the orangutans used pantomime to achieve specific communication goals:

  • An adolescent female named Siti, who had partially opened and eaten a coconut, handed it to a technician who in turn handed it back to her, gesturing to her that she should finish the job. She proceeded to briefly, weakly and ineffectively poke at the coconut (very much in contrast to her prior behavior), before handing it back to the technician. When he again refused to help her, she used a palm petiole (stalk) to chop at the coconut repeatedly, as one would with a machete. Russon and Andrews described their interpretation of the incident in the data supplement to their paper:

After [the technician’s] first refusal she faked inability to do the job herself; after the second refusal she elaborated her request by acting out what she wanted done, specifying what tool and target to use and how to use the tool.  She acted out the actions she wanted of her partner, which included a skill that was not in her own repertoire (machete use).  Given the complex conjunction of conditions and the specificity of her request, Siti’s pantomime must have been invented on the spot even if she was familiar with all constituent elements.

Fortunately, you can see this incident for yourself, as there’s a video of Siti and the coconut – enjoy!

  • After a three year old female named Kikan had hurt her foot on a sharp stone, a research assistant removed the stone and dripped latex from the stem of a fig leaf on the wound to help make it heal faster. After that, Kikan (who had previously not been particularly friendly with the assistant, hitting or trying to bite her when she passed by) approached the assistant in a friendly manner on a number of occasions, holding up her wounded foot for the assistant to see. On one specific occasion, Kikan picked up a leaf, pulled the assistant’s hand until she paid attention, and then acted out the leaf treatment the assistant had given to the foot. (This is not only interesting for its communication content, but it could be an indication of episodic-like memory (mental time travel), a topic that Felicity Muth recently discussed in some detail in two Scientific American blog posts, here and here).
  • An adult female named Unyuk played with forest assistant who pretended to give her a haircut with a Swiss Army Knife. While they played she noticed a backpack, an item regularly stolen by orangutans in hopes of finding food. Unyuk made no immediate move for the pack – instead she continued to act out her role in the haircutting game, grabbing the hair on top of her head and inviting the assistant to continue playing as she gradually moved sidewise and closer to the pack. Once she had a free path, she lunged and made a grab for the unattended pack. (This was one of seven pantomimes that the researchers labeled as deceptive, where the actor feigned an inability, an interest or an intent in order to obtain help, distract, or express friendly intent and facilitate reconciliation.)

Russon and Andrews believe that some of the pantomime cases contain attributes of natural language:

including compositionality (large meaningful units are composed of smaller meaningful units…), systematicity (the actions and entities pantomimed are meaningfully rearranged following predictable patterns…) and productivity (…unique creations of the moment). Thus, orangutans can communicate content with propositional structure and have the kind of cognitive capacities with constituent structure typically associated with linguistic capacities.

Although spontaneous pantomiming appears to be fairly rare among orangutans (again, a total of 18 examples were unearthed from 20 years’ of data), the underlying data came from studies that were not focused on communication, and the researchers believe that other studies may have missed similar pantomiming to the extent that they focused on the functional aspects of gestures rather than the significance of pantomime as a medium for communication.

In any event, the study offers an eye-opening lesson in how sophisticated – to the point of being linguistic – non-verbal communication can be. If nothing else, we should not be too overconfident if we ever have a chance to play charades against a team of orangutans.

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1Russon, A., & Andrews, K. (2010). Orangutan pantomime: elaborating the message Biology Letters, 7 (4), 627-630 DOI: 10.1098/rsbl.2010.0564.

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