Becoming a Tiger: The Education of an Animal Child

by Susan McCarthy

  ANIMALS COME UP WITH NEW STUFF all the time. A behavior might be so inevitable that animals invent it again and again. In fact, every animal of that species might invent it. Or it might be an innovation that’s a little less obvious, which a few animals come up with from time to time. Or it might be so unusual that it is invented rarely or only once.

  Sometimes innovation is a matter of applying well-established actions to new targets—eating a new food. That might seem trivial, but it can be pretty hard to get humans to eat new foods, and not only small children with suspicious taste buds. Whole populations refuse to consider eating fermented milk products, or jellyfish, or toasted locusts.

  It’s a cat-eat-monkey kind of world

  It has frequently been suggested that man-eating tigers, lions, and leopards come into being when an injured or sick great cat, unable to catch wilier and more appealing prey, invents the idea of eating people. The famous tiger hunter Jim Corbett, who was often called to track and slay man-eaters, wrote that 9 out of 10 he shot had a serious injury, either from a gunshot or porcupine quills, and the tenth would be a case of extreme old age. “Human beings are not the natural prey of tigers, and it is only when tigers have been incapacitated through wounds or old age that, in order to live, they are compelled to take to a diet of human flesh.”

  A tiger in Muktesar unwisely tangled with a porcupine and got 50 quills driven into her face and foreleg, some right up to the bone. She lost an eye and was lying in thick grass licking her wounds, starving, when a woman cutting grass for cattle cut up to the spot where the tiger was lying. The tiger killed her with a single blow and limped away to lie under a fallen tree. Two days later a man cutting wood started to chip wood off that tree; the tiger killed him, and took a little taste. The next day she killed and ate a person who hadn’t intruded on her sickbed or bothered her at all, and before she met her end she killed 24 people.

  But in the Sundarbans region of India, an enormous delta system on the Bay of Bengal covered with mangrove forests, tigers regularly eat people, and it seems unlikely that they’re all getting over porcupine fights. It has been pointed out that they don’t eat very many of the people who enter the area, but individual humans are still reluctant to be among that small number. For a brief period, they didn’t have to be. Tigers attack people from behind, an excellent tactic, particularly if the person is carrying a machete. Arum Ran of Calcutta suggested that people venturing into the forests of the Sundarbans (to fish, collect honey, or cut wood) should wear masks on the backs of their heads. That way the tiger would see a face on each side of the head and wouldn’t see any place to attack.

  In the first year this was tried, no one wearing a mask was attacked. “Some men reported that tigers would still follow them, sometimes for hours,” writes Sy Montgomery. “Often the person would hear the tiger growling, as if it were frustrated that the Janus-man had somehow cheated it, yet it seemed unable to perpetrate a similar breach.” But apparently the tigers learned that a face mask is not a face and resumed dining on even costumed humans.

  The famous man-eaters of Tsavo, lions who killed and ate more than 135 people, were shot in 1899, and their remains went to the Field Museum of Natural History in Chicago. More than a century later, museum staff examined the skulls and found that one lion had a shocking mouth, with missing, broken, and displaced teeth and what must have been a painful dental abscess. The other lion would have kept a dentist busy, but his deficiencies were not incapacitating. Perhaps the first lion couldn’t hunt anything but humans, and the other simply followed his lead.

  Trendsetters

  Who are the innovators? While many people prefer the animal Einstein notion, it turns out that you can actually collect data about which animals are likely to come up with new things. Hans Kummer notes that primates may be good innovators because they are “remarkably ill equipped with innate technologies.” If they had a macaw’s beak, they wouldn’t see any advantage in cracking nuts between stones, and if they had an anteater’s tongue, they’d never spend hours dipping straws into ants’ nests.

  Within a primate troop, Kummer expects social innovation among animals of low dominance rank, because the animals of high rank are happy with things just the way they are. In studies of captive macaques, lower-ranking animals were better at a lever-pressing task than dominant animals. The subordinates tried harder, for more irregular rewards. When dominant macaques lost status, they got better at the task.

  Animals with lots of free time and energy are also more apt to come up with innovations, as in (the better) zoo colonies. Kummer and colleagues compared hamadryas baboons in the Zurich Zoo with wild colonies, and found that the captive animals had social signals that the wild animals did not have but that the reverse was not true.

  Changes in the environment can spur chimpanzee thinking. In the early days of Goodall’s research at Gombe she put out steel boxes which researchers could open remotely and which could be stocked with bananas. After four and a half months, three teenaged chimpanzees began trying to lever the lids open with sticks. While the boxes were too sturdy for this to work, “because a box was sometimes opened when a chimpanzee was working at it, the tool use was occasionally rewarded and, over the next year, the habit spread until almost all members of the community, including adult males, were seen using sticks this way.” This would seem to be a case of superstitious tool use.

  J. P. Cambefort hid tasty foods in the foraging areas of a troop of chacma baboons and a troop of vervets. The treats (banana slices for vervets, maize meal pellets for baboons) were marked with clues such as painted sticks, matchboxes, or bottle tops, so that the monkeys could learn to use the clues to find the foods. Juvenile baboons, who forage separately from the adults and are still learning how to find food, were quick to figure out the clues. The other baboons noticed this and propagation of the news was “instantaneous.” In the vervet troop, the ones who figured it out first were just as likely to be adults as juveniles, but the news was slower to spread.

  Who thinks this stuff up?

  Researchers Kevin Laland and Simon Reader set up opportunities for guppies to show whether they were innovators. Fish had to swim through mazes to find unfamiliar but tasty food. Hungry guppies were more apt to explore and find the new food. Little guppies were more apt to do so. And female guppies were more apt to do so. The researchers, remarking that necessity is the mother of invention, take the view that needy guppies are more likely to innovate. The females need nourishment because they have to give birth, the small guppies need nourishment to become big guppies, and the hungry guppies—must we explain that they would kill for a snack?

  In additional experiments in which they tried to control for motivational state, the researchers investigated whether there are “innovator fish.” They found that fish that innovated before were more apt to innovate in a new test, which the researchers consider to indicate an innovative personality.

  “At this stage it is not clear whether such differences reflect variation in mental abilities,…sociality,…boldness,…exploratory behaviour,…some other factor, or some combination of these factors,” they write.* “None the less, it is interesting, and perhaps surprising, that we find evidence for innovative individuals in a species not particularly renowned for its intelligence or problem-solving capabilities.”

  In contrast, Dorothy Fragaszy and Elisabetta Visalberghi found no innovators among captive capuchin monkeys—capuchins that figured out how to sponge liquids weren’t the same ones who figured out how to rinse sandy fruit.

  Imo, all things to all thinkers

  This brings us to the story of Imo, which has been told many times with different morals. Imo was a young Japanese macaque who lived on the small island of Koshima. Scientists had been observing the troop in which Imo lived for some time and putting out food to attract them to areas where they could be more easily seen. One food they used to lure them out of the forest and down to a beach was sweet potatoes. The potatoes got sandy, and the mac
aques brushed the sand off with their hands as well as they could, but this is why beach picnics are not unalloyed joy. In 1951, Imo, 18 months old, was seen taking her sweet potatoes to a stream and rinsing them.

  Soon one of Imo’s playmates was also seen washing her potatoes. Imo’s mother started washing her potatoes. Eventually most of the macaques washed their potatoes. Then Imo began to wash her potatoes in the ocean instead of the stream, perhaps for the salty taste.

  The researchers started tossing wheat onto the beach, which was hard to eat without ingesting massive quantities of sand. At the age of four, Imo was seen gathering up handfuls of sandy wheat and putting it in puddles or in the ocean so that the sand sank and the wheat floated. She could then scoop the wheat off the surface of the water. Imo’s little sisters Ego and Enoki picked up this method, as did Imo’s (male) playmate Jugo. The habit also moved from offspring to their mothers, and generally from younger to older relatives.

  Imo has been called an Einstein among macaques. A monkey genius! Psychologist Cecilia Heyes has suggested that it is also perfectly possible that Imo accidentally discovered the utility of putting sandy potatoes in water when she serendipitously dropped one there, and that other monkeys in the troop similarly learned by chance. Already in the habit of putting things in the water, the monkeys might have separately learned to wash sandy wheat. In this analysis, the fact that Imo did these things first merely makes her a genius of luck.*

  That washing sand off potatoes is not such a bizarre and brilliant cognitive leap is shown by the fact that macaques on five other nearby islets also figured out that it was a good idea. “Imo did not exactly discover the monkey equivalent of the wheel,” writes Frans de Waal.

  Freakishly, pop science mystics spun the story that once a certain number of monkeys had learned to wash potatoes, suddenly all the monkeys on all the islands knew how. The knowledge had magically spread through macaque group consciousness. For fun, they picked the number 100. Thus, proposed the “Hundredth Monkey” advocates, if enough of us humans think beautiful thoughts, suddenly, when we reach the magic number, everybody will think beautiful thoughts. This is a relaxing, low-cost way to get things done, but sadly it’s not true about the macaques and is unlikely to be true about us.

  Meanwhile, back at Koshima, the monkeys only get sweet potatoes a few times a year, but they still wash them. Adults in the troop, scavenging the leavings of fishermen, learned to eat raw fish, and this spread to other members of the troop. The macaques are becoming increasingly littoral, spending more time on the beach, swimming and bathing in the sea, not only eating fish but prying limpets off rocks and catching octopuses and small fish in tide pools. Give them time, and they will become a great seafaring nation.

  The Compleat Angler

  Some green-backed herons practice bait fishing. In 1958, in an idle hour, biologists tossed a piece of bread to a heron, who surprised them by putting it in the water. He moved it closer when it drifted away, chased away coots that wanted to eat it, and caught small fish that came to sample it. When he noticed a lot of fish in an adjacent area, he carried the bread over there.

  Herons not supplied with bread have been seen using twigs, leaves, berries, pieces of bark, moss, or Styrofoam for this purpose. Others have been reported to catch insects or worms for bait. If all a heron has is a twig, and the twig is too long, the heron may break it to a more alluring size, according to an observer in Kyushu, Japan—though American and African herons haven’t been spotted doing this. A heron in Miami was photographed using fish food pellets to attract fish to their doom. His mother and little brother bait-fished too.

  Juvenile green-backed herons aren’t the best fishermen, as they often neglect to crouch down, and thus scare the fish away. “The young birds sometimes resort to eating the insects and earthworms themselves,” reports zoologist Hiroyoshi Higuchi. Of three herons Higuchi observed, A and B were handicapped by inferior fishing territories but also by their tendency to use overly large bait. Heron C, in addition to having a territory that made it easy to crouch out of sight of the fish, selected his lures more judiciously.

  Although green-backed herons are found all over the place, they’ve been spotted using this technique only in Japan, south Florida, and western Africa. People have tried to teach herons to do it, without success. There are scattered reports of a few other birds fishing with bait: some African pied kingfishers, a captive squacco heron, and a captive sun bittern. Maybe it is the sort of thing that a bird that spends hours staring at the water is inclined to invent once in a great while. And that other such birds are then inclined to pick up from them. Biologists James Gould and Carol Grant Gould suggest that it is “discovered by the Einsteins among the herons, and learned from them by only the brightest of their neighbors.”

  Smashing snails

  European song thrushes are renowned for smashing snails on stones (called anvils). Some people thought they learned it from other thrushes, and some thought they were born knowing how. C. J. Henty raised song thrushes from the egg and offered them snails, pebbles, bits of wood, and anvils. The fledgling thrushes were enthusiastic about these things, pecking them, lifting them, carrying them, tossing them, shaking them, and hitting them. At first they focused on smashing pebbles and wood, which are easier to grip than snails. Once they smashed and ate a snail, their focus improved enormously. Although they still experimented with smashing new things, such as a collar stud Henty offered them, they no longer bothered with things they knew were inedible.

  Henty notes that fledgling blackbirds—a species that doesn’t regularly eat snails—did all the things that song thrushes do (pecking, lifting, etc.) but not with the same persistence. Trial and error combined with inherent tendencies seems to produce snail smashing in song thrushes. “Any animal that innately picks up large hard objects in the environment,…repeatedly…hits them on the ground, prefers the feedback from hard surfaces, and prefers doing the behaviour to items that provide food, is inevitably going to be a self-taught breaker of snails,” writes Henty. (Henty neglects to mention that the animal should also enjoy eating raw snails.)

  Catch the cunning sand lance

  In the 1980s, humpback whales in the waters of southern New England were closely observed by researchers who went out on whale-watching cruises. Around this time the local humpbacks were adjusting to a crash in herring populations and were catching sand lance instead. A common way for whales to hunt sand lance is to blow a cloud of bubbles at them from underneath, then surge up with mouth agape and take a huge mouthful. (The water runs out through your baleen plates, and you eat the fish.) In the early 1980s whale watchers began to see a variation, which they called lobtail feeding. In lobtail feeding the whale makes a dive near the surface, so that its tail rises up out of the water. Just as the flukes at the end of the tail are about to slide under, the whale flexes its tail and violently slaps the water. Then it follows up with a bubble cloud and a feeding lunge. Whether this actually yields more sand lance is unknown.

  In 1980 they hadn’t seen any whales doing this. In 1982 they saw 8 whales (in a population of 250) lobtail feeding, and by 1989 more than half the whales were lobtail feeding. A lot of the younger whales were taking it up, and a few of the older whales were too. Two-year-old calves were seen off by themselves, practicing. They’d lobtail over and over, often without making a bubble cloud, and without making a feeding lunge. When they did make a bubble cloud, it was puny. By the time they were three, the same calves were like experts. Some of the lobtailing calves had lobtailing mothers, but based on the large number of calves and the small number of older females lobtailing, they couldn’t all have been learning from their mothers.

  Tool use

  Tool use was for many years held up as a dividing line between the human and animal intellects. We used them, the others didn’t. As various discoveries of animals using tools were made (some bugs use tools, darn it), the line was shifted to making tools. We make tools, they don’t. Then various animals s
tepped over this line, and we began to hear less about the matchless intellectual prowess involved in toolcraft. But perhaps some of the early glorification of tool use (when we thought it was our strong point alone) was overblown, as hinted in the title of an 1987 article in New Scientist by Michael Hansell, “What’s So Special about Using Tools?”

  Hansell is unimpressed with the mental underpinnings he thinks exist when an Egyptian vulture drops a rock on an ostrich egg to break it; or when a woodpecker finch breaks off a stick and uses it to harry insects out of cracks in bark; or when a wasp closes the burrow in which she has laid her eggs by pounding the sand with a pebble she holds in her jaws. He concedes that some animals learn to be better with tools, but says that “there is no evidence here that there is something extraordinary about the learning process.” Instead he says the last hope of proving that tool use is “something apart from other behaviour” is finding examples of insight, an animal equivalent of “James Watt looking at the boiling kettle and conceiving the steam engine.” Sadly for this endeavor, few animals have invented the steam engine.

  Nevertheless, along with language and social learning, tool use is one of the three areas where scientists look for evidence of cognitive skills. Indeed, many anthropologists suspect that the evolution of tool making and the evolution of language were closely meshed. This would be nice, because while spoken language leaves no traces in the physical record of the past, we can find some ancient tools, particularly those made of stone. (Wooden and fiber tools don’t last, causing us to envision our forebears incessantly chipping, hacking, and flinging stones and not to envision their nets, snares, backpacks, furniture, and who knows what else. If there was a Basket Age, we’ll have to wait for better archaeological techniques to find out about it.)