The Social Behavior of Older Animals

15 Adapting and Not Adapting

chapter 15 Adapting and Not Adapting S ome old animals readily adapt to novel situations, but other individuals and groups may find this impossible. Presumably this difference relates in part to how things are processed in the animals’ brains. Even though turtles and tortoises have existed for a very long time, a particular member could come up with unique responses to unusual events. Individual primates (gorillas, chimpanzees, and bonobos) can be highly flexible in their behavior, as can elephants and dolphins. However, under artificial conditions imposed by humans, other individuals (for example, among dolphins and chimpanzees) may be unable to adapt completely, and whole pods of whales (pseudorcas) have been destroyed because of this inability to adjust. Adapting turtles Metaphorically, you can teach an old dog new tricks. Older animals, even members of an order of reptiles that has existed for nearly 200 million years, may absorb new experiences. Pigface, a Nile soft-shelled turtle (Trionyx triunguis), spent almost his entire life at the National Zoo in Washington DC (McCarthy 2004). For his first 40 years, Pigface was kept in a barren enclosure, with his only stimulation being the pursuit of the 12 live goldfish he was fed once a week; he chased them “with speed and agility” until he caught and consumed them all. This took twenty minutes. Pigface later injured himself by biting at his front legs and raking his neck with his front claws. Worried by this behavior, his keeper decided to give him some toys. This sensible act turned his life around. He began to nose and bite a basketball and push it around the tank. A floating hoop was even better: he could “chew it, shake it, pull it, kick it, and swim back and forth through it.” He began playing tug-of-war with the hose the 155 keepers used to refill his tank, and he loved to have the stream of water cascade over his head. Pigface had learned to play! He died a few years later, in 1993, when he was over 50 years old. Another relative, this time a land-dwelling older tortoise at a menagerie in Mombassa, Kenya, also adapted easily to a new experience—the adoption of a 300 kg baby hippopotamus who had been orphaned when swept out to sea by tsunami waves in the Indian Ocean in December 2004 (Hatkoff et al. 2005). Although the tortoise, Mzee, was about a century old, 100 times as old as the newcomer, he quickly befriended Owen, the infant, who normally would have stayed with his mother for two or more years. The two animals swim, wander about, and eat and sleep together, their bodies touching. Despite his advanced age, the tortoise was quick to adapt to his new role as a guardian. gorillas Numerous captive silverback gorillas have become locally famous by the time they grow old, but none is more famous than Jambo. Not for what he did, but for what he did not do to a little boy. He is so well known that Richard Johnstone-Scott (1995) wrote a book about him. On a hot August day in 1986, Levan Merritt, a young lad anxious to see the family of gorillas at the Jersey Zoo in Great Britain as closely as possible, leaned too far over the rail above the gorilla cage and fell over 3.5 m (12 ft) into the dry moat below. The crowd gasped in horror. Everyone watched transfixed as the aged Jambo, followed by his family, ambled over to the boy to see what was up. This looked like a young human. Why was he lying so still? Jambo leaned over to sniff the body carefully, shifting so that his massive form stayed between the boy and the other curious gorillas. Then he sat back on his haunches for nearly a minute, examining the throng of horrified faces that were staring down at him and yelling “Jesus Christ!” “Oh my God!” “Get away from him!” Jambo turned again to the boy, gently lifting part of his clothing and brushing a dark finger along the pale exposed skin. Then he lifted his hand to his nose to smell the scent. Soon the boy began to gain consciousness , whimpering and struggling to move. At this, the murmur from the human chorus above became a babble of shrieks: “Don’t move!” “Keep quiet!” “Watch out!” “Do something!” “Where are the keepers?” Startled 156 the social behavior of older animals [3...