Hilltop Male, a coyote who made his home in a suburban Chicago park, knew how to get around the 'hood. Every night he and his mate set out to hunt, traveling together until they reached a two-lane road. He looked left and right, waited for cars to pass, then darted across to all the tempting fare around the area homes. His mate would watch him leave before turning back to the park. Not once in the year that a research team observed the pair did she ever cross that road.
Meanwhile, Hilltop Male was having a fine time. "He definitely wreaked havoc; he took peoples' cats," says Stanley Gehrt, a wildlife biologist at The Ohio State University in Columbus who's been studying Chicago's coyote population for 13 years. Hilltop Male even devoured a local hospital's prized swans, brazenly feasting on one in plain view of passing patrons. Ultimately, however, his adventurous nature proved fatal; he was struck by a car and killed.
"He was bold, but not every coyote is," Gehrt explains, noting that neither Hilltop Female nor her new mate, Hilltop Male2, has ever ventured across the road separating the park from the suburban houses. "There is tremendous variation in coyotes' behavior," he says, "and the only way to explain it is by understanding their personalities."
For most of the 20th century, the idea that nonhuman animals had personalities was considered anthropomorphic. When primatologist Jane Goodall suggested in the early 1960s that chimpanzees were temperamentally different from one another, she was criticized by animal behaviorists and comparative psychologists. But these days, animal personality research is booming. "Personality is a phenomenon in nonhuman animals," asserts Alexander Weiss, a comparative psychologist at the University of Edinburgh in Scotland who was part of a team that showed that chimpanzees have dispositions remarkably similar to those of humans. "Anyone who has been to the zoo or owns a pet can see it."
A bird in a flock, a fish in a shoal, or orangutans separated by miles of forest—each individual animal is now accepted by researchers as having persistent quirks, tics, likes and dislikes that set it apart from others of its kind.
There are agreeable Scottish wildcats and others that are ornery and aggressively dominant, as well as elephant matriarchs whose confidence, constancy, and openness reflect their age and role. Male crickets can be bold, delivering mating calls often and loudly, or shy, singing softly now and then; while some fruit flies are explorers, venturing far to find a new home, others are sitters, barely moving from where they hatched.
"In almost every species we've looked at, we find that individuals are consistently different in their behaviors over time and across situations," says Andrew Sih, a behavioral ecologist at the University of California, Davis. Just as introverted children typically remain so as adults, animals also stick to their personality types—as did Hilltop Male. (Yet, he notes, "they also have some unpredictable element. That's the essence of personality.") The universality of this phenomenon has triggered a host of questions about the origin and purpose of personality; in addition to cataloging the vast array of types within and across species, researchers today are focused on why such differences emerged in the first place.
The Many Masks Of Man And Beast
The study of animal personality is a young field, barely two decades old. It didn't really get underway until the late 1990s, although several early prominent scientists, including Ivan Pavlov and Robert Yerkes, envisioned a holistic science of personality that embraced all animals.
Scientists who watch animals, though, were paying attention to their quirky ways and, when they could, publishing observations. At the Seattle Aquarium in the late 1980s, for instance, biologist Roland Anderson noted that volunteers gave names to giant Pacific octopuses that reflected their individual habits. There was Lucretia McEvil, who destroyed items in her tank; Emily Dickinson, who tried desperately to stay hidden from view; and Leisure Suit Larry, who eagerly latched his arms onto anyone unlucky enough to be nearby when his tank was open.
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