Becoming a Tiger: The Education of an Animal Child Page 14

  James’s utterance of “Hullo, Boy” and other mimicry were witnessed by many people. The plausibility of “Hullo, Boy” is also supported by the later case of a male lyrebird, this one resident in the Sir Colin Mackenzie Zoological Park, who took up replying “Hello, Chook” to the keeper who said this to him every morning. He also imitated his cagemate, a bush thick-knee.

  Given that Pratt was wrong about lyrebirds raising their children together, it’s interesting that decades later a male lyrebird at the Zoological Park rose to the occasion when the female he was housed with died suddenly. The chick was three and a half months old, still in need of parental care. The chick called for its mother, lost its appetite, and “developed a hunched appearance.” The male let the chick roost next to him at night. He then alarmed the zookeepers by pursuing the chick with the same calls the mother had made. He began regurgitating food for the chick just as mother lyrebirds do, and after some hesitation the chick allowed itself to be fed and flourished under its father’s care. The zoo documented this unheard-of behavior, which almost leads one to exclaim with Pratt that the lyrebird is extraordinary, complex, and socially virtuous. Although Pratt might have been even more impressed had father and child died of grief.

  Female lyrebirds also mimic. In a footnote to Pratt’s book, written by “Mr. A. G. Campbell, onetime President of the Royal Australian Ornithologists’ Union,” we read that “In a nest under observation in Sherbrook Forest during August, 1936, owned by a well-known pair who are used to the stare of strangers, a lusty youngster was reared. The mother, after a visit with food, would occasionally pause above the nest and sing a few delightful strains of mimicry. Thus the young Lyrebird got his first few lessons from his mother.” According to current doctrine, a female lyrebird mimics when her nest is threatened, so perhaps she wasn’t as used to the stare of strangers as all that.

  Territorial mimicry

  African robin-chats are impressive mimics. Some territorial robin-chats match their neighbors’ mimicry, so if one robin-chat imitates a fish eagle, the one next door will imitate a fish eagle right back. I’ll see your fish eagle and I’ll raise you a francolin. Oh? Well, I’ll see your francolin and raise you an oriole. Since one robin-chat was recorded imitating 36 other bird species, this could conceivably go on for quite a while.

  The Beau Geste hypothesis suggests that when birds sing many types of songs they may give other birds looking for territory the impression that the place is crowded, so they should move on. Whether mimicry of other species could have such an effect is unknown.

  Other uses of mimicry

  A pet African black crow who ranged free found a use for mimicry. The crow had its eye on a flock of chicks, but the chicks correctly perceived the crow as a menace and went into their chicken house whenever they saw it. When the owner had scraps for the chicks, she’d call “kip-kip-kip-kip-kip,” bringing them dashing to scrabble over the bits. When the owner was away, the crow learned to sneak up, call “kip-kip-kip-kip-kip,” and grab the first chick that came running.

  Derek Goodwin has suggested that in some birds which mimic in captivity, but which don’t seem to mimic in the wild, there may be mimicry that goes unnoticed. If birds in a pair are separated, “whichever of the two is left in its home area will soon begin to utter calls or song phrases that are normally used only or mostly by its mate. This has the effect of ‘calling the mate home’ if it is in a position to return.” But it sounds like normal bird calls unless you know the individuals.

  Goodwin writes of tame European jays that associate the calls they mimic with the creatures who make them. Goodwin’s tame jays barked at dogs who came into his garden and meowed at cats. He writes that some jays mobbing tawny owls imitate the hoots of the owl when they do, and cites a case in which a group of jays arrived at the usual daytime roost of an owl. Finding the owl not at home, they hooted and left for another roost. Finally, he writes that tame male jays, when they get angry with their keeper, “invariably defy him with display phrases consisting partly or wholly of words and whistles that he has often used in their hearing, usually those with which he customarily greets them.”

  A related use of mimicry was noticed by Terry Oatley in robin-chats. Fledglings have cryptic, camouflaged plumage, and when they leave the nest young birds perch quietly in heavy cover, occasionally uttering short, high, location calls, stirring only when their parents bring food. Robin-chats have a ratchet sound, which the adults use as an alarm call. When the little birds hear it, they fall silent and freeze. The adult robin-chats intersperse the ratchet call, which the young respond to instinctively, with imitations of the alarm calls of other birds in the area—no other calls are imitated, only alarm calls. If a mongoose, snake, or human being approaches, the parents go into a frenzy of ratcheting and mimicked alarm calls. By this means, the young birds may learn that other birds’ alarm calls, and not just the ratchet, are heralds of danger.

  Oatley also observed a subtle use of mimicry in chorister robin-chats. He was spying on a pair nesting near his garden, and saw them reunited after a separation of 20 minutes. The female, returning from a foraging trip, perched in the foliage and whistled softly. The male, standing sentry near the nest, peered around and cried “too-wheee,” which is the call of the southern boubou shrike, not a robin-chat remark at all. The female said what a boubou shrike says to its mate in response to too-wheee: “boo-boo-boo!” They continued to exchange boubou shrike calls. Had Oatley not been focused on these birds, he would have assumed he was hearing shrikes and would have had no idea that these two used shrike calls as contact calls.

  Mammalian mimicry

  “Harbor seals have long been regarded as unusually quiet pinnipeds,” begins an article in the Canadian Journal of Zoology. But adult males are not only chatty, they will mimic human speech. Two males at Boston’s New England Aquarium made sounds resembling English words and phrases. One confined himself to saying hello; and the other, Hoover, had so many remarks that he was written up in The New Yorker.

  Hoover was found as a newborn on a beach in Maine. His mother had been shot by a fisherman. Local residents Alice and George Swallow raised him for three months, naming him Hoover for the way he vacuumed up his mashed mackerel. They kept him first in the bathtub and then in a pond in the backyard, allowed him in the house, and let local kids take him for wheelbarrow rides. When Hoover made noises, George Swallow copied him and apparently Hoover copied Swallow right back. When he came home from work, Swallow would slap the side of his car and shout “Hey, stupid!” Hoover would waddle up and Swallow would say “Hello, there” to him. One day Hoover replied, approximately, “Hello, dere,” but Swallow didn’t think much of it. Swallow taught the seal to reply to “What’s your name?” with “Hoover.”

  When Hoover’s costly mackerel habit overwhelmed the Swallow budget, they took him to the aquarium. “I told a fellow there, ‘I think he can talk,’ but he gave me such a look I never mentioned it again,” Swallow told The New Yorker. Eight or nine years later, the Swallows went to the aquarium. George Swallow shouted, “Hey, stupid!” and Hoover swam over, took Swallow’s hand in his mouth as he used to do, and tried to pull him into the water.

  One day when Hoover was seven, a keeper wrote in the files, “He says ‘Hoover’ in plain English. I have witnesses.” The matter was investigated and it was decided that Hoover did indeed say his name and also said “Hello,” “Hello, there,” “Hello, there, how are you,” “Come over here,” “Get out of there,” and “Hey.” He also laughed. Researchers writing in the Canadian Journal of Zoology noted that these are things that aquarium visitors often said to the seals, and The New Yorker noted that these were things often said by George Swallow. All parties agreed that Hoover had a Boston accent.

  It’s easy to imagine that Hoover, who talked more in breeding season, learned what important grown-ups (like George Swallow) should sound like when he was an impressionable pup and repeated these things when he became an important grown-up himself
.

  Belugas

  Beluga whales in captivity have also been known to get chatty. Logosi, a beluga who arrived at the Vancouver Aquarium as a tiny calf, said “Logosi,” which is what people said to him. Logosi was flatteringly interested in conversing with people, swimming up to the windows of the beluga tank, repeatedly pressing his face against the window and making sounds, then turning and placing his ear against the glass as if to hear a response. “Logosi” was not the only thing he said, but it was the only thing anyone could understand. Logosi also did imitations of human conversation. Devoid of words, it sounded like people talking far away, or children playing.

  Duets

  Many bird species that form lasting pairs sing duets that may announce and cement their relationship. Wolfgang Wickler has proposed that when partners learn their duets, each is proving a commitment (or an investment in, to use the more calculating phraseology) to the other that would not be shown if duet parts didn’t have to be learned. To switch to another mate, you’d have to start from scratch to work up a nice duet.

  To really learn your part is also to learn your partner’s part. A male white-browed robin-chat sings a four-note motif over and over, rising to a crescendo, at which point the female joins in antiphonally with loud “tsreeee”s. If she has a beakful of caterpillars, or for some other reason doesn’t join in, the male sings both parts.

  Of course I love you—have I ever missed a rehearsal?

  Pairs of siamang gibbons sing loud and elaborate duets, which announce their territorial claims and advertise the excellence of their relationship, since their performance is so well coordinated. Observers at the Louisiana Purchase Gardens and Zoo recorded how a new couple learned to duet.

  A proper siamang duet, or great call, is said to begin with two deep booms from the male. The female replies by booming once; the male booms twice more, and the female must immediately come in with accelerating high-frequency barks. After about the fifth bark, the male should utter an ascending boom, the female’s barks should speed up, and the male should do a bitonal scream. At once the female must start another series of barks, and after five the male should do a scream, this time a ululating scream. The female does some fast high barks, then both of them bark and hurtle about. While hurtling, the male should do a locomotion call as well as barking.

  Simple enough, you say. Well, it takes practice. The male of this pair had been caught in the wild as a mere child and had lived at the zoo for 17 years. He had had a mate, but she had died, and he had been alone for 12 years. The female was six and a half, and had lived with her parents until her arrival in Louisiana. They were put in adjacent cages and began working on their duet right away. (After a while the doors were opened so they could go back and forth.)

  If one of the siamangs made a mistake in the great call sequence they’d often drop the whole matter. Over about three months the percentage of started duets that were finished rose from 24 percent to 79 percent, and in the last five bouts no mistakes were made. One of the most common mistakes was for the female to start her first set of accelerating high barks without waiting for the male’s second double boom. The other common mistake was for the male to bungle his bitonal scream, giving either the ululating scream or the locomotion call instead.

  Testing, testing

  Guacamole, a stray dwarf macaw rescued by Martha Coyote, imitates other animals in the household and interesting phrases people say, but also finds it intriguing when people imitate him. If you mimic him, “about the third or fourth time he starts looking at you with interest.” He then runs you through a few tests: can you say hello? can you bark like the poodle? can you cough? can you squawk twice? can you squawk three times? can you squawk twice low and once high? can you whistle? “He’s trying to see if you can keep up,” Coyote reports.

  Similarly, Karen Pryor describes a wild humpback whale recorded by Bill Schevill in the Bahamas, in which the whale is calling into an underwater canyon. “The whale went ‘Mroomp!’ and the echo went ‘Mroomp!’ The whale tried it again, one note higher, until it had gone up the octave as far as it could reach. The echo answered. Having tried out higher and higher ‘mroomps,’ the whale essayed a few other roars and gargles, waiting for the echo each time.”

  Codes and signals

  Many animals have calls that tell others that there’s something they should know about—an opportunity or a peril. Ravens give food calls to recruit other ravens to food sources in dangerous places, because there’s safety in numbers. Scientists in Austria studied the yells made by wild ravens at a boar feeding station in a game park where the ravens routinely stole food from the wolves, bears, and boars.

  The rate of “haa” calls went up as soon as they could see the food, before they could get it, confirming previous suggestions that these long yells mean that the ravens have detected food they can’t get. The more desirable the food, the higher the rate of “haa” yells. Ravens gave short “who” yells at their usual rate until the food was actually available in the boars’ pen, when the rate went way up, particularly as they landed and advanced on the food. The rate of “who” yells went up more when there was only one bucket of food, suggesting that these yells may have something to do with claiming food.

  Cats

  A house cat bringing prey to her kittens has two different calls, so distinct that even humans can tell the difference, according to ethologist Paul Leyhausen. One means “I am bringing you a harmless little snack,” and is used with a mouse. The other means “I am bringing you something that should be treated with caution,” and is used for a rat. The mouse call brings kittens out fearlessly, and the rat call brings them out in a hesitant crouch. The rat call is actually an intensified version of the mouse call, and if the mother gets all worked up, perhaps because Leyhausen has closed the door between her and her kittens, the mother will race back and forth with the mouse in her jaws crying “Mouse! Mouse! MOUSE!” until she is crying “Rat!”

  A cat’s purr, Leyhausen speculates, originated as a signal from a suckling kitten to its mother, meaning that all is well. It has the advantage of being something a kitten can say with its mouth full. Now it is used by mothers approaching their kittens and suckling their kittens, by kittens approaching adults to play, by dominant cats reassuring other cats they approach, and in some situations by cats that are threatened or severely weakened, as by disease. This last may explain occasional mysterious purring at the veterinarian’s office. “At first sight this may seem paradoxical, considering that in its original meaning the purr signals well-being. But probably in all the cases mentioned the message is basically one of appeasement and in human terms would mean: ‘I am only small, helpless, inoffensive, and innocuous!’”

  Alarm calls

  The alarm calls given by wild vervet monkeys to warn of predators have been intensively and cleverly studied, using playback tape recorders concealed in bushes. Robert Seyfarth and Dorothy Cheney have described five different calls that vervets use to denote the dangers of large terrestrial carnivores such as leopards, eagles, snakes, baboons, and unfamiliar humans. The leopard, eagle, and snake calls have been carefully studied. Each calls for a different reaction. If you hear a leopard call, you should dash up a tree. If you hear an eagle call, you should scan the sky as you take cover in a bush. If you hear a snake call, you should stand and scan the ground for the snake. If you are tiny, clinging to your mother works for all dangers.

  These calls are vital news. Only about 30 percent of baby vervets make it past the age of one year, and most of the missing were eaten by predators. Little vervets make perfectly enunciated alarm calls when they are only one month old. But they are shaky on when to give them. Adults only give eagle calls for eagles and hawks, but juveniles give them for almost any big bird—spoonbills, take cover!—and infants may call for almost anything airborne—Mommy, a dove! A leaf!

  Infants who are three to seven months old may be playing away from their mother when they hear an alarm call (often a tape playe
d back by Cheney and Seyfarth). Younger vervets usually run to their mothers, but as they get older they are more apt to take adult-type evasive actions. Initially they make mistakes, running into a bush instead of up a tree when they hear a leopard call, a bad idea, since leopards often hide in bushes. By six months, they almost always get it right.

  The alarm calls of other species

  Baby vervets ignore starling song, but at one or two months old they respond to starling alarm calls by looking toward the sound. By the time they are four or five months old they respond to starling terrestrial alarm calls by running up a tree. Eventually they distinguish between starling alarm calls denoting ground predators and those warning of eagles, and behave appropriately.

  Zoologist Maurice Burton’s family raised a family of orphaned baby rabbits to adulthood. Burton’s neighbors also had a rabbit, but theirs had been caught when it was already half-grown. The alarm call of a blackbird sent the neighbors’ rabbit scuttling for a dark corner, but Burton’s own rabbits showed no concern, suggesting that the rabbit caught at a greater age had learned that the blackbird’s alarm call was cause to worry. Burton’s rabbits, perhaps because they had never noticed Burton and his family quivering with horror at a blackbird’s alarm call, had not learned to understand this important signal.