Becoming a Tiger: The Education of an Animal Child Read online

  These mean streets

  When going forth to seek their fortune, one of the first things young animals must do is learn their neighborhood. Some will stay where they were born, and others will eventually go forth and look for new places, but even the ones who seek new territories need to learn what good places to live are like, and how to get around in them, the wild equivalent of how to cross the street.

  Jungles are scary places for jungle animals that have never been there before. Arjan Singh raised a leopard, Prince, who was simply appalled when Singh first took him walking in the forest. There could be monsters anywhere! Only because he was with Singh and the noble dog Eelie did he dare go into the woodlands. Then the monsoon arrived. Here he’d thought he knew the worst they could throw at him and now there was water everywhere all the time. Prince was just a year old and now accustomed to making unescorted forays into the forest and even killing some of his own food, but he still returned regularly to Singh—until the monsoon, when he vanished. “I grew more and more fearful that he had died,” writes Singh. When he had been gone eight days, someone “heard a faint sound across the river and saw a miserable little leopard perched in the fork of a tree. When Eelie and I went to rescue him in the boat, he cried with relief, giving pitiful aoms. From his ravening hunger, it was clear that he had not eaten for the whole week.”

  As a result of the reasonable caution a creature may feel in a strange environment, animal rehabilitators who set captive-reared animals free must often wait a long time before the animals feel bold enough to leave their cages or pens. In a release of captive-reared orangutans into an Indonesian rain forest one ape came out, looked around, went back into the transport cage, and closed the door.

  Clare Kipps, who raised a crippled baby sparrow in her London apartment, eventually bought a small potted tree for him to perch in. He was terrified at the sight and dived down the collar of her shirt to hide from the tree. He wouldn’t go near the ghastly thing, and she reluctantly bought a cage, which he adored.

  Przewalski’s horses (the only surviving wild species of horse) have been raised in captivity and released to their ancestral range. They’ve adapted well and a second generation has been born. The principal problem rehabilitators encountered was the horses’ reluctance to leave the release area. They all wanted to stick around and fought each other for the privilege.

  The released Przewalski’s horses were showing “site tenacity.” But in addition to learning that a particular neighborhood is home, young animals can learn that a particular kind of neighborhood is home. European mistle thrushes used to nest in the middle of pine forests. When many European forests were cut down, grown mistle thrushes returning to their hometowns to raise families often found themselves not in a pine forest, but in open parkland. Exhibiting site tenacity, some of the thrushes raised families there anyway. Luckily, the species thrived there. The next generation, exhibiting locality imprinting, had learned that open parkland was a fine sort of place to nest, and they increased and spread.

  In the same way, curlews in Scandinavia returned to the bogs where they had always nested, only to find that the bogs had been drained and converted to fields. Insisting that no one was going to kick them out of their ancestral bog, they nested anyway and their chicks grew up to consider agricultural land their traditional nesting place.

  Anemonefish are a group of fish species, and each species lives inside the sheltering tentacles of a different species of sea anemone. They lay their eggs on a nearby rock, and when the young fish hatch, they hang around the rock a little and then spend a few weeks swimming around before they settle in an anemone. But right after hatching, they learn the smell of the anemone their parents live in, the one near the rock on which they were born. When it’s time to settle down, they seek an anemone of the species that smells right. If, due to the machinations of researchers, an anemonefish is born in an aquarium where there is no anemone to smell, it is not quite sure what to do when it wants to settle down and the only place available is an anemone. It can take one of these fish two days to move in to the perfect anemone, whereas a fish with the right upbringing takes only five minutes.

  Learning the neighborhood may not be enough. Young animals may need to learn exactly where in the neighborhood they are safe—which street corner is the best to hang out on. In many cases when captive-reared animals are released in the wild, they lack the critical information that they should stay off the ground.

  Endangered Hispaniolan parrots born and raised in captivity and released into the wild spent a lot of time foraging on the ground or in low bushes, a mistake a wild-born parrot would not make, and one which exposes the birds to great danger of predation. Indeed, researchers, trying to figure out why some released parrots they had fitted out with radio transmitters had vanished, followed the signals out of the forest and to the home of a Haitian family who had caught the birds and eaten them.

  In the early days of a golden lion tamarin reintroduction project in Brazil, tamarins raised in captivity and released in the forest were obtuse about unexpected things. They were slow to leave the outdoor enclosure in which they had been allowed to adjust to the local climate, and when they did leave, they perched on top of the pen. It was not obvious to them, as it was to the scientists who were watching aghast, that for hawks and eagles this was the equivalent of a neon sign reading EATS. The scientists dismantled the pen, forcing the tamarins to move into the trees. Here it turned out that the tamarins did not grasp the principles of moving through the forest. Despite the incredible athleticism they had shown in captivity, natural vegetation struck them as untrustworthy and they became hesitant and unimaginative. They disliked the way things moved under their weight. “The animals were unable to plot a cognitive route through the forest between themselves and an incentive. Their movements were characterized by false starts, fruitless retracing of pathways to dead ends, and, finally, descent to and travel across the ground,” the researchers noted. “At best, travel by the reintroductees was slow and hesitant. At worst they got disoriented and lost. Some simply sat, appearing to give up, and had to be rescued. Two perished on the ground, one taken by a feral hunting dog and one…likely killed by a snake.”

  In subsequent work with tamarins, the structures in the pens in which they were reared were made of natural materials and were changed every week to make them learn to leap from branch to branch as tamarins must. The result was better survival.

  Janis Carter, trying to reintroduce captive-reared chimps into the wild, had little luck persuading two of the more civilized specimens, Lucy and Marianne, not to sleep on the ground. Merely getting up in the middle of the night, booting them out of their ground-level beds, and chasing them up trees didn’t work. They’d just descend as soon as she left. Finally the desperate, sleep-deprived Carter took to creeping up to the sleeping chimps and pinching them with a pair of pliers. “I hoped to simulate the bite of an animal,” Carter writes. It worked.

  Captive-raised red wolves released in North Carolina didn’t need to stay off the ground, but would have been wiser to stay off the street. The wolves, who weren’t nearly worried enough by humans, found roads to be an extremely convenient way to bypass the annoying undergrowth in the forest, and so they were all too apt to be hit by cars or tailed down the road by incredulous motorists trying to figure out if that was really a wolf or just a weird dog.

  Black-footed ferrets raised in captivity and released in a Wyoming prairie dog village adapted wonderfully in many respects, but were much more apt than wild ferrets to swank around on the surface. Wise ferrets—old ferrets—stay underground as much as possible to avoid predators.

  Like the tamarins, captive-reared California condors have shown a distressingly relaxed attitude toward artificial structures. Reared in rectangular human structures full of squared-off perches and surfaces, they find these congenial when they are freed, landing on roofs, balconies, and worst of all, power poles. The trouble with landing on power poles is that it often l
eads to colliding with power lines. So many young condors died in collisions that rehabilitators began doing aversive conditioning before releasing condors, by putting power poles in the aviaries, wired up to give condors shocks. This lowered the rate of collision deaths.

  But other congenial human structures included roofs at the Burger Barn in Cuyama, and in Pine Mountain Club, where the young birds landed 15 at a time. Once, they practiced their disemboweling skills on an air conditioner. On other occasions, they were accused of swooping down and ripping the windshield wipers off parked trucks. Eight condor hooligans broke through a screen door and into the (unoccupied) bedroom of one Pine Mountain Club resident. When he discovered them, the resident, Les Reid, is said to have ordered them, in a calm stern voice, to leave, whereupon “the raptors slunk out in single file.” One of the condors released in Arizona, near the Grand Canyon, is reported to have dropped by a campground one day. A backpack was just sitting there, so this badly brought up young bird rifled through it, probably hoping to find cash or drugs. Instead, the bird found a loaded revolver. Naturally the punk took the gun and swaggered around the campground, carrying it by the trigger. Luckily, no one got shot.

  Curiosity and willingness to try new things has good and bad aspects for condors. Biologists were bursting with pride when released birds fed on dead sea lions washed up on the coast, and not happy at all when the birds dropped by a ornamental backyard pond and ate all the frogs in it.

  Learning fearlessness about human structures and habitations has been a good deal for a few species, notably rats, mice, and pigeons, but also for such creatures as the red fox. Some British red foxes have made a specialty of urban life. David Macdonald and his colleagues disconcerted Cambridge residents, who found them tracking radio-collared foxes in the middle of town. Macdonald writes of Unipart, whose mother gave birth to him and his siblings in a factory warehouse in Oxford. The others moved on, but Unipart made the warehouse his home, one where he could keep watch from the tops of stacks of pallets or from girders. The workers gave him food, and tossed “balls of greasy chip-paper” for him to chase. One day Unipart, prowling around a nearby auto assembly plant, got injured. He took refuge in some ventilation pipes. His meddlesome human friends caught him and took him to a veterinarian. Restored to health and his warehouse home, the last we heard of Unipart he was becoming more outdoorsy, going out in the streets and cantering behind bicycles.

  What’s for lunch?

  Once you get your bearings, it’s time to eat. As anyone who has ever argued with a small child at mealtime knows, it’s not always obvious what’s good to eat and what’s not. Some young animals pursue the strategy of trying to eat everything they see; others are more conservative, only eating things they’ve eaten in the past or at least seen others eat.

  Young sharp-shinned hawks are open to the charge that their eyes are bigger than their mouths. In a study in which biologists staked out sparrows, starlings, and pigeons along a shoreline that hawks follow when migrating south along Lake Michigan, young hawks were much more likely to try for pigeons, “birds that are grossly too large for suitable prey,” whereas experienced adults went for smaller starlings and sparrows. The greedy young hawks had only been hunting for themselves for a month or two and hadn’t learned to avoid “potentially difficult prey.”

  Other creatures are less alert to snack possibilities. Mississippi sandhill cranes raised in pens and released to the wild hung out with wild-born sandhill cranes, but weren’t open to new menu items. Pen-reared birds joined wild birds in pecan orchards, but did not seem to grasp the concept that if you poke around in pecan orchards, you might be able to find free pecans—and you can eat pecans. They preferred corn, such as they had been served in the pens.

  Fruitlike objects, leaflike objects

  Baby howler monkeys in Costa Rica readily try to eat any fruit they see, or indeed any “frugiform object” they come across. They waste some time trying to eat woody galls and seed cases, but this doesn’t do them any harm and eventually they quit trying. They are much more cautious when it comes to leaves. They may taste a leaf they have not seen an adult eat, but they won’t eat it. Instead of just grabbing and gnawing, the baby follows its mother closely from tree to tree, and watches to see which leaves its mother eats. When she feeds, often hanging by her tail, the baby feeds next to her, often hanging by its own tail. As the mother pulls a branch to her mouth to eat the leaves, the baby pulls leaves off the same branch and eats them. The different attitude that baby howlers have toward leaves is probably vital because, unlike fruits, many leaves contain high concentrations of compounds that aren’t good for monkeys.

  Many young animals learn what others are eating—which is presumably good to eat—by sniffing the mouths of others. Benjamin Kilham, who has raised many black bear orphans, eventually discovered that the cubs liked to smell his breath and then eat whatever they found he’d been eating. He chewed on beech buds, and when the cub Yoda smelled his beechy exhalations, she excitedly began eating beech buds herself. By chewing red clover, he conveyed the news that red clover was good food.

  Before he understood this, Kilham was shocked when his first pair of bear cubs examined, but did not sample, a rapidly drying puddle full of thousands of dead and dying tadpoles. How could they pass up all that fabulous protein? The answer is that he failed them—had he chewed just one moribund tadpole and let them smell his breath, they would no doubt have eaten all the rest.

  Mere breath-sniffing was not enough to satisfy those urban chimpanzees being reintroduced to the wild on an island in the Gambia. Primatologist Janis Carter was working with a motley group of chimps, some of whom had spent a few years with their mothers in the wild before being captured, others who had less wild experience, and Lucy, a city girl who had been raised like a child in the home of psychotherapist Maurice Temerlin. Lucy knew more than 100 words in American Sign Language. She was 11, and more accustomed to taking cartons of raspberry yogurt out of the refrigerator than to hunting and gathering.

  Carter would lead her charges through the jungle. Seeing a leaf species she knew to be favored by wild chimps, she would utter food barks, tear off young leaves, and eat them in an ostentatious manner, giving forth this-is-so-delicious food grunts. The chimps with wild experience would start eating the leaves. Those who had been indoctrinated in the dainty ways of humans were more skeptical. They would pry Carter’s mouth open and look to see if she was really eating leaves. (“She is! She’s really eating them! I can’t believe it!”) Usually that was enough to get skeptical Lucy to try the leaves. But even when Carter bravely ate them herself, it was not enough to get Lucy to try eating safari ants.

  Orangutans being rehabilitated in the Indonesian rain forest learned from each other about wild foods. When Aming, a new orangutan, was brought to the camp in Sungai Wain Forest (because in his previous release area he’d been raiding orchards), he brought knowledge about certain things that were good to eat, and other orangutans learned from him. Ignorant young apes scrounged bits of what others were eating and then, if they liked it (and they usually did), tried to find some for themselves. Experts like Aming were swarmed by little apes every time they were seen eating. Shortly after his arrival, he started eating bark off a big tree next to a main trail. One of the other orangutans, Enggong, heard the bark tearing and came over and stared. Enggong dangled next to Aming for a better look. He drew closer and stared until Aming left, and then he took Aming’s spot and ate bark himself.

  One young orangutan, Jaja, didn’t recognize most of the potential foods around her, and wasn’t inclined to learn. But she was fond of a student at Camp Leakey, Femke den Haas, and den Haas showed Jaja how to eat rattan shoots. Den Haas picked a rattan shoot, tore open a sheath at the base of the shoot, and ate the tender part. Jaja picked a rattan shoot and opened it, but ate the wrong part. Den Haas did it again, and handed the edible part to Jaja to eat. Jaja picked another, and this time did everything right. She spent the rest of the day gorging
on rattan shoots.

  Nobody wants to be the first to try a new food. Biologist David Macdonald, studying red foxes, was delighted to discover that every evening five foxes visited the back garden of fellow biologist Hans Kruuk, seeking what they might devour. Macdonald and Kruuk encouraged these visits by scattering bread crusts, bacon rinds, and other table scraps. Perhaps the biologists felt guilty about these unnatural foods, for they were delighted when they got their hands on some dead mice, much more suitable fox food. They scattered these among the scraps and waited to see the foxes’ delight. The foxes were repelled and alarmed, just as you might be. “They shrank fearfully from the mice until the bravest fox summoned up the courage to dash between them and snatch up the crusts of bread,” writes Macdonald. Days passed before the foxes were willing to try the mice, combining them with bread in “a most wholesome-looking sandwich.”

  I’m never eating that again

  As well as learning what’s good to eat, animals learn what’s not good to eat. The loathing that animals, including people, feel for foods that have nauseated them in the past is a primal horror. Psychologist John Garcia, who called this phenomenon learned taste aversion, discovered in the 1960s that rats learned to hate a food that was followed by nausea even if the nausea didn’t occur until hours later (and even if the nausea was caused not by the food at all, but by radiation sickness, or by an injection researchers had given the rats).

  This was upsetting to the then-prevalent orthodoxy which held that animals could only learn an association if the behavior (eating rat chow) was immediately followed by the reinforcer (the negative reinforcement of feeling sick). Nor did it fit that rats were much more apt to associate nausea with a food than with a visual stimulus. One diehard famously wrote that Garcia’s results were about as likely as “find[ing] bird shit in a cuckoo clock.”