But no. Inborn instinct told Leo nothing. Leo stood and stared at the hysterical impala, excited but baffled. “His instincts were obviously signaling that something very important was happening and that there was something urgent that he should do.” In that state of confusion, he spotted Krüger, lit up with certainty, bounded through the herd, and pounced on her.
One of Leo’s favorite foods was an impala leg. But perhaps the fact that he liked eating impala legs but didn’t think of leaping on an impala and killing it is no more surprising than the fact that children who like to eat chicken drumsticks seldom think of leaping on hens and killing them, even if they’re really hungry.
A few days later, the threesome startled some buffalo. Krüger managed to keep Wolfie from pursuing, but Leo ran after them, herded them downriver, and came back for praise.
Lacking a suitable role model, Leo did not learn to kill. The idea of letting him go free had to be abandoned. He eventually found a home at a game park maintained for the benefit of photographers and filmmakers, where he was fed, hung out with lionesses, and behaved in a photogenic manner.
Like Leo, Penny, a leopard raised and released by Joy and George Adamson, did not seem to know what to do after a certain point in the hunt. One day when she was a little over a year old she spotted an aardwolf sitting in the sun and having a wash. With admirable form she crouched, used cover to get close to him, sprang from hiding, and gave him such a slap. The aardwolf took off running, and Penny gazed at the Adamsons in perplexity, “as though to ask, ‘What next?’”
Even when released great cats are not able to catch quite enough prey to feed themselves, they are able to raise cubs that can. The second-generation leopard Mameena, whose mother was raised by humans, was self-supporting. Pippa, a cheetah raised by humans from cubhood and rehabilitated by Joy Adamson, experienced no difficulty in relating to other cheetahs, successfully mating with wild males and raising several litters in the wild. Her only deficit was in hunting. She wasn’t very good at it, but Adamson supplied her and her cubs with a steady stream of goat carcasses for most of her adult life. When she didn’t get these supplies, sometimes she managed to get enough food on her own and sometimes she didn’t. Her cubs, however, who began hunting at an earlier age, became self-sufficient and raised litters of their own.
An Englishcat in India
Perhaps the only captive-reared tiger ever to be released to the wild was Tara, born in the Twycross Zoo in the UK. Arjan Singh had Tara shipped to India, where he raised her at his home, Tiger Haven, adjoining a forest preserve prowled by wild tigers. He had previously raised and released leopards there, with the aid of his yellow dog Eelie.
Tara spent her days playing and walking in the forest with Singh and Eelie. At night Singh kept her in the house or, after she was older, in a large cage.
Like cubs reared by their mothers, Tara seems to have started out as a floppy, bounding, undisciplined creature who enjoyed chasing animals and seeing them flee. If Eelie chased an animal, Tara would join in. Wild pigs did not appeal to her at first, but they appealed to Eelie greatly, so Tara chased them too. On one occasion she chased a bicyclist until he fell off his bike, and she lost interest.
Tara was rather bad at taking cover, which Singh tentatively ascribed to Eelie’s influence.* When she was nine months old, Tara made her first kill, a chital fawn that had gotten tangled in some creepers when Tara put the rest of the herd to flight. Eelie felt he had just as much right to it as Tara, but Tara carried it up a tree and wouldn’t share.
Tara had a feud with a troop of otters who chittered maddeningly at Eelie and her one day as they walked with Singh by the river. Later that day she abandoned her companions, stayed out all night, and was found the next day covered with tiny bite marks in odd places. As Singh reconstructed it, Tara had gone back to teach the otters a lesson, and had caught one. Not yet having permanent teeth, she sat on it. It bit her, as did the rest of the gang, until she let it go. Some months later, when Tara had her new canine teeth, she intercepted a group of otters who were crossing a field and killed one. The rest of the otters surrounded her, chittering, and she “looked from side to side, all the time grinning nervously.” A possible mob scene was averted by the arrival of a human on Tara’s team.
As she grew older, Tara was more and more drawn to the forest, leaving earlier in the morning and coming back later at night. She was just over 20 months old when she stopped coming back—as anyone might have guessed, she had met a guy. A slightly older guy, one who got his own dinner and was delighted to share with Tara. She didn’t come home, didn’t write, didn’t call. Whenever Singh heard that livestock had been killed by tigers, he rushed to the scene to see if Tara had been there. At first it was easy to tell, since Tara’s methods were inexpert. If it had been killed with a single throat bite, that wasn’t Tara’s work. If a tiger had leapt on the hindquarters of an animal lying down, and clawed at it wildly before killing it with a nape bite, that was Tara. Singh fretted—a nape bite is dangerous on a buffalo, Tara. It could gore you.
She had been with Singh for 17 months before she stopped coming back. “It will be obvious that nowhere do I claim to have taught Tara anything, for the simple reason that a human cannot teach an animal: his lifestyle is too different,” writes Singh. But experience and, perhaps, the examples of the wild tiger, did teach Tara, and with time she became self-sufficient. She successfully raised at least three cubs.* Happily for the neighbors, she seems to have had no further interest in associating with humans.
How to fix dinner
Some food requires preparation. Mountain gorillas at Karisoke, Rwanda, who eat herbaceous plants, have no difficulty finding food. When they sit in the rain forest, they are surrounded by it, and it isn’t trying to get away. Very little of it is toxic or indigestible, so learning what’s good to eat is not a major task for a gorilla child. But many of the best food plants have stings, spines, hooks, or tough cases, so learning how to eat these is harder. Mountain gorillas are fond of nettles, but dislike being stung. Adult gorillas pick nettle leaves and fold the stinging top and edges into the middle of a bundle before they eat them. Gorilla children haven’t figured this out yet, and get stung when they first start eating nettles. The only adult gorillas at Karisoke who didn’t fold their nettle leaves were a female with maimed hands and a female named Picasso, who transferred into the area as an adult. Picasso grew up at a lower elevation, where few nettles grow. Investigators Richard and Jennifer Byrne suggest that in her youth Picasso didn’t get to observe other gorillas folding nettles and so didn’t learn to do it herself. Interestingly, her son Ineza, three years old, was not very good at processing his nettles.
The Byrnes suggest that the gorillas learn how to process difficult foods by trial and error, but that young gorillas may be showing program-level imitation. Thus a gorilla child gets the idea to fold nettles from noticing that its mother folds nettles before eating, but it doesn’t precisely copy her movements. Instead it figures out for itself how to fold nettles; as a result, each gorilla has its own idiosyncratic ways of executing the same processing techniques.
Thick-billed parrots eat a lot of pine nuts, which they extract from pinecones. Learning to do this takes young parrots several months. Captive-reared birds who were given pinecones for six months before being released eventually learned how to get food out of them—but then when they were free, couldn’t figure out where to find pinecones.
Squirrels? How could it be squirrels?
In the early 1980s a high school biology teacher in Israel, Ran Aisner, took students on a field trip to some plantations of Jerusalem pine. These had been planted in the last 50 years and did not constitute a particularly natural habitat. Aisner noticed piles of pinecone scales and bare pinecone shafts under some trees on the edge of the plantation and brought them to zoologist Joseph Terkel. Clearly, Terkel said, some creature had been stripping the scales off the cones to get at the pine nuts inside, and the culprit in such a case is general
ly a squirrel, but there are no squirrels in Israel.
Eventually, by placing traps in the branches of the pines, Aisner caught some black rats. There turned out to be a population of shy rats that ate only pine nuts, drank only water they licked from pine needles, and lived in tree nests made of pine needles.
Through surreptitious observation it was discovered that the rats selected a ripe cone, gnawed it off the branch, carried it to a better spot for a sustained bout of gnawing, and took it apart in a quick and systematic manner. This technique involves starting at the base of the cone and pulling the scales off in a manner that entails a minimum of gnawing. The scales wind around the shaft of the cone in a spiral, and the efficient thing to do is to take them off in a spiral path. After a few turns—a few rows of scales—the rat will find a pine nut under each scale. The bits fall to the forest floor, potentially alerting sharp-eyed nature buffs.
In Terkel’s laboratory they began to investigate these rats and their methods. Rats of the same species who were trapped in urban sites such as warehouses were clueless about cones and not interested in obtaining clues. If they were really hungry, and there was nothing else in the cage, they would eventually chew on the cones, but their method was simply to start gnawing inward from a random point, a procedure so inefficient that they would have starved had the researchers not eventually given them rat chow. Not one developed the spiral technique.
If the city rats were housed with a rat from the piney woods who knew how to strip cones, that didn’t help. After three months of bunking with an expert, they still had no inkling how it was done.
Unsurprisingly, rat pups who grew up with mothers who got their pine nuts by stripping pinecones with the spiral technique also stripped cones with the spiral technique. Of 33 rat pups raised this way in the laboratory, 31 could do it. Two could not and gnawed at random.
The helpful researchers then provided a set of clues to adult rats who could not imagine how to strip cones. They gave them pinecones that had been started. The first four rows of scales had been stripped off, so a rat that proceeded to remove scales in a spiral manner would find a pine nut under each one. Of 51 grown rats, 35 could finish the job on a started cone, using the spiral method.
Twenty of these rats then received further tuition. Having succeeded in doing this with cones that had had four rows removed, they were then given cones with three rows removed, and if they succeeded with those they got cones with two rows removed, and so forth. Finally they got intact cones. At the end of the course all of the rats could open cones that had had just one row removed, and 18 passed the final exam. They could open an intact pinecone and extract all the seeds with the spiral technique.
How this whole thing got started is unknown. There might have been an innovative female rat who came up with the technique and passed it on. (An innovative male who came up with the technique would not have had a chance to pass it on.) Or perhaps there was a female who ate some pine nuts and some other foods (since without good technique a rat cannot get enough pine nuts to survive) and who left partly eaten pinecones around, and this was sufficiently illustrative to let the pups figure it out.
More techniques
Sea otters are famous for their use of rocks to smash shellfish. In the canonical example, a sea otter floating photogenically on its back places a flattish rock on its chest, holds a clam in its paws, and smashes the clam on the rock. When an otter has found a good rock, it will carry it around in the web of loose skin under its forearm (the term “pawpit” is tempting, but not quite right). An otter may keep track of a really good rock for years. Sometimes a second rock is used to hammer the hapless shellfish.
Underwater, otters also use rocks or other objects as tools to pry or bash abalone and sea urchins loose from rocks. If they catch more than one crab, otters will wrap the ones they aren’t eating in strands of seaweed to keep them from getting away while they eat the first one. In Monterey Bay, Female 532 was seen using a piece of abalone shell to scoop abalone meat out of its shell.
Pups stay with their mothers for six months or more, getting much of their food from their mothers and improving their skills. In one study the pups came up with food on 13 percent of their dives, while their mothers got food on 70 percent. Pups aren’t initially sure what things are food. Marianne Riedman describes a pup named Josie industriously propelling an old car tire to the surface and giving it a serious chewing before deciding that it wasn’t food.
Female 190 passed on her liking for rock oysters to her daughters Josie and Tubehead. To knock them off the rocks, Female 190 favored a glass bottle as a tool. (People are always tossing cans and bottles into the water, which is disgusting but not without utility to otters and octopuses. People seldom toss in can openers, corkscrews, hacksaws, and other really useful tools.) When they were old enough, Josie and Tubehead also used glass bottles to get their oysters.
Whose brilliant idea was childproof packaging?
For some predators, killing their prey is easy compared to actually eating it. It’s too big. They don’t know where to start. The skin is tough. Or maybe it’s covered with weird stuff—feathers or hair or scales or something. Biologists often refer to this as “opening” carcasses.
Prem, a hunting guide who assisted Fiona and Mel Sunquist in Nepal, once tried to feed some wild orphaned tiger cubs, about six months old, by tying out a goat for them. When he came back the next day he found the goat dead but uneaten. Somehow the cubs had managed to kill it, but with their baby teeth and lack of experience, they had been unable to open it. They had, however, licked it bald.
Even if eating it isn’t a problem, getting dinner home can be difficult. One wild Malayan tiger developed a labor-saving way of moving the carcasses of his prey. He dragged them into the nearest stream, and then towed them through the shallow water until he got to a good place to begin eating. In the water they were easier to pull and perhaps less likely to catch on roots and saplings. This was a great source of annoyance to the tiger hunter who was trying to follow him, as he left no tracks.
Save some for later
Niff, a red fox cub raised by David Macdonald, was already caching food when she was one month old, although she had never seen anyone else cache food and had never known shortage. Macdonald’s house, not being floored with dirt for burying things, offered her insufficient scope, but she persevered, stuffing food into corners with her nose and then attempting to conceal it by pushing notebooks over it. Eventually she came up with the brilliant idea of hiding food in the bedclothes, an idea many human children have devised. It was awkward, because she shared the bed with Macdonald, and he did not like the idea of finding a dead chick under the pillow, nor did she like the idea of him stealing her dead chick.
When Niff was older, Macdonald took her for walks through the fields. Sometimes he had arranged for the path they took to be sprinkled with dead mice and other taste treats, to see what Niff would do. After eating a few, Niff began caching mice, and given the proper setting she performed superbly. She’d carry the mice off the path, dig a shallow hole and bury the mouse in it, sweep dirt over it with her nose, and then muss up the grass stems over the spot, which prevented the site from being obvious. This behavior, clearly innate, gave Niff great satisfaction. She remembered her caches, and might go back to check on them more than a week later.
At one point, when local farmers had caught many mice raiding their chicken houses and donated them to Niff’s cause, she was particularly well fed and began to get slapdash. One day she didn’t even cache all the mice she found, and those she did cache she buried so carelessly that their tails stuck out. By evening, when they walked the path again, Niff was hungry and went straight for her caches. Horror awaited—magpies had stolen her mice. She ran from spot to spot, but all the mice were gone. The next day, all the mice she did not eat were buried with exacting craftsmanship. Niff had learned the importance of doing something well she innately knew how to do.
Career choices
&nbs
p; Supporting oneself is of course vital, and animals who survive often have the help of many innate hints. But learning is still tremendously valuable—if the food available in the environment changes (if caterpillars start pretending to be sticks, if leaves evolve toxins, if you’re confronted with ostriches instead of peacocks), you’ll have a chance of figuring out how to eat.
SIX
How Not to Be Eaten
In the Brazilian forest, biologist Karen Strier was watching a group of muriqui monkeys, whom she had been quietly following for six months, trying to habituate them to her presence. It was hot, and the muriquis were resting, when a male from another group dropped by. Suddenly he spotted Strier and launched into a threat display, uttering frenzied calls, swinging wildly around, breaking branches and dropping them near Strier. She worried that his alarm might be infectious, and undo her patient work of months. Four females hurried over to see what was so awful. Arriving at the scene, they hesitated and huddled together, looking back and forth between the raucous male and the source of his alarm. After a few seconds the four charged at the male and threatened him. He seemed astonished, froze, and then took off, hotly pursued by the females.
A few minutes later, they returned. “The females began to embrace one another, chuckling softly as they hung suspended by their tails, wrapping their long arms and legs around each other. Two of the females disengaged themselves from the others. Still suspended by their tails, they hung side by side holding hands and chuckling. Then they extended their arms toward me, in a gesture that, among muriquis, is a way to offer a reassuring hug.”
Becoming a Tiger: The Education of an Animal Child Page 22