Animal Behavior: Love at the Zoo

Nothing frustrates zoo curators quite so much as trying to mate stubbornly uncooperative animals. Though many wild beasts are compliant enough about breeding behind bars, others seem to lose their reproductive urge as soon as they lose their freedom. But their sexual indifference to their own kind, Zurich Zoologist Heini Hediger told a symposium on animal behavior in San Francisco last week, may obscure a simple fact: they sometimes learn to prefer their keepers to their natural mates.

As director of the Zurich Zoo, Hediger did not have to search far for examples of such unproductive infatuations. One of his zoo's prized possessions, a 5-ft.-high African shoebill stork, barely acknowledges the presence of a female acquired especially for him. Instead, he saves all the normal male shoebill signs of affection— lowered head, lively clapping of the wooden-shoe-shaped bill, peculiar gulping noises —for his caretaker. Sometimes animal passions become actively embarrassing; recently, while a repairman was crouching in an emu's enclosure, the huge, ostrichlike Australian bird decided that the intruder was a female emu and behaved accordingly. At times the sexual play verges on the pathetic. "We have seen instances," says Hediger, who is also a professor of animal psychology and biology at Zurich University, "where tortoises have regarded the shoe of their keeper as a mate."

Leonine Hazards. Such biological befuddlement is more evident among animals who have either been raised by humans or brought to zoos as youngsters. Under a keeper's warm and sympathetic care, Hediger explains, they gradually shed their innate fear of man and begin to accept him as an equal in every respect. Occasionally, after such "imprinting" or "assimilation," as animal behaviorists call these processes, male animals regard their keeper as a sexual rival. A male lion, for example, usually sits benignly by while the keeper strokes his lioness. But if the keeper shows affection for the lioness while she is in heat, the male may rear up, roar menacingly and act as if he is ready to tear his cage—and his keeper-apart.

Since animal society is essentially hierarchal, says Hediger, humans who face dangerous creatures in their cages should assume a super-alpha status—in other words, a rank above that of the topmost animal. If he fails to assert such authority, the zookeeper risks finding the animals as impudent, mischievous and eager to take advantage of any sign of weakness as school children with an unsure and inexperienced teacher. And the animals' pranks, Hediger adds dryly, can produce far more painful consequences.