The Science Behind Aesop’s Menagerie

Sseveral chapters In Aesop’s Animals: The Science Behind the Fables, zoologist and science writer Jo Wimpenny explains that as a very young girl, she sometimes wanted to be a dog. (In a footnote, she credits growing up in Wales for encouraging her to “think outside the box.”) This childhood fantasy, as the reader can easily imagine, involved crawling on the ground on all fours. But that’s only part of the way to doghood, as the adult Wimpenny would come to realize.

To begin with, we humans rely primarily on our senses of sight and hearing, but for dogs, smell reigns supreme; as she explains, a dog’s sense of smell is between 10,000 and 100,000 times better than ours. Dogs “can also wiggle their nostrils independently, helping them identify the direction of a scent”, and there is evidence that the left and right nostrils serve slightly different purposes, with the right being adapted to “new and potentially threatening”, and the left responding to “familiar, non-aversive odors (such as food) and odors of other species (such as human sweat for tracking purposes)”. Who knew?

BOOK REVIEW“Aesop’s animals: the science behind the fables”, by Jo Wimpenny (Bloomsbury Sigma, 368 pages).

Wimpenny’s entertaining book is a sort of guided tour of the animal world, but the topics aren’t chosen at random. Rather, it focuses on a subset of the animals mentioned in “Aesop’s Fables”, a beloved collection of tales attributed to a slave named Aesop, who is said to have lived in Greece around 2,500 years ago. So with dogs we get to know wolves, crows, donkeys, lions, monkeys, ants, grasshoppers, hares and turtles. Each chapter takes its name from a specific fable – “The Raven and the Pitcher”, “The Wolf in Sheep’s Clothing”, etc.

Wimpenny cites the work of researchers who have spent decades studying the behavior of these animals, as well as his own research; and, as the childhood dog’s story suggests, many of his own experiences as well. Although we learn a lot about what various animals can do, the deepest insights come from trying to discern Why they do them. In a nutshell, we yearn to know what’s going on in their heads.

Do animals, for example, have a sense of self? The answer varies from species to species of course, but some results seem reasonably robust. For example, chimpanzees seem to pass the mirror test: when exposed to their own reflections, they come to understand that the animal that appears to be behind the glass is actually them.

Darwin asked similar questions more than 180 years ago, although it was the behavior of young orangutans, rather than chimpanzees, that he observed at London Zoo. Beginning in the early 1970s, psychologist Gordon Gallup Jr. conducted a series of mirror tests with chimpanzees; as Wimpenny explains, he observed that over time they would “inspect parts of the body that were only visible with the mirror, including the inside of their mouths and their genitals; they picked up food on their teeth and mucus on their eyes; and they were also making funny faces and blowing bubbles.

Gallup then conducted more sophisticated experiments and, over time, convinced his colleagues that chimpanzees do recognize themselves in mirrors. Most interesting, however, is how rare this is in the animal kingdom. He concluded that orangutans could do this, but many of our primate cousins, such as macaques for example, do not recognize their reflections, even after years of exposure to mirrors. As Wimpenny puts it, they “just don’t get it.”

More controversially, one Asian elephant in particular has been said to have passed the mirror test, as well as the cleaner wrasse – a fish that eats parasites found on larger fish. But as Wimpenny explains, if an animal fails the mirror test, that doesn’t necessarily prove that it lacks a sense of self. Wolves, coyotes and dogs, for example, show no interest in their reflections. As scent animals, why would they?

Speaking of dogs, Wimpenny devotes several pages to the fascinating history of how humans have domesticated these animals over many thousands of years. This story has been told many times, but it features a twist that will be new to many readers: it turns out that genetic variation may have played a significant role in turning dogs from predators to allies. As molecular biologists recently discovered, dogs (but not wolves) have a genetic defect that matches a gene in humans with Williams-Beuren syndrome – a rare disease that makes people hypersociable and not are not afraid of strangers. “The finding that wolves and dogs differ in this equivalent segment of the genome,” Wimpenny writes, “suggests a potential mechanism underlying the change from wolves to friendly, people-loving dogs.”

Considering the amount of groundbreaking research on crows and other corvids over the past decade, it’s no surprise that they too feature prominently. Crows, like humans and chimpanzees, are tool users. They can bend wire and even make their own hooks to retrieve hard-to-reach food. As Wimpenny points out, we’re not so shocked to find chimpanzees exhibiting such behaviors. After all, our line split from theirs just 6 million years ago – or maybe even later. Our last common ancestor with birds, on the other hand, lived 320 million years ago. There is also evidence that corvids can recognize human faces and even languages.

Even more remarkable is what we have learned about how these birds think – and what they are capable of thinking. Of particular interest is work on a relative of the crow known as the western scrub jay by Nicky Clayton, first at the University of California, Davis and now at the University of Cambridge. Clayton showed that jays are able to remember the past: they can hide food in a place where they know they can retrieve it later — and, having buried different types of food, they will preferentially choose to dig up the faster – rotting foods first, saving longer lasting foods for later. In a more elaborate experiment, Clayton and his colleagues showed that birds not only remember the past, but also plan for the future. They placed the jays in three different compartments – one in which they always received “breakfast” and two in which they did not – on different days. Towards the end of the week, the birds unexpectedly received additional food in the evening, at a place where they could access all three compartments. The jays quickly hid their surplus, preferably stashing it in the “no breakfast” compartment. Because the birds were not hungry at the time of hiding, Clayton concluded that they were really anticipating how hungry they would feel the next morning.

“The finding that wolves and dogs differ in this equivalent segment of the genome,” Wimpenny writes, “suggests a potential mechanism underlying the change from wolves to friendly, people-loving dogs.”

Do scrub jays remember the past and think about events in the distant future, as humans regularly do? Probably not – and as Wimpenny admits, many of these results are still debated. Yet it now seems implausible to claim that only humans grasp the past and future, with the rest of the animal kingdom stuck in the present.

There is, unfortunately, quite a bit of repetition – many subjects, including Clayton’s work with those scrubby jays, come up repeatedly. This seems to be largely the result of linking each chapter to one of Aesop’s fables. Without this constraint on the structure, the author could perhaps have found a simpler narrative.

Yet each chapter is packed with compelling facts and arguments. (My favorite dish is this factoid: Charles Darwin and Steve Irwin both spent time caring for the same turtle. Her name was Harriet and she died in 2006, aged at least 176 .)

The book’s greatest strength is its detailed exploration of the animal spirit. Wimpenny carefully shows us how they differ from ours – and yet how, in many ways, they are not so different at all.

Angela C. Hale