Odd Couples Among Wild Kingdom Baffle Biologists

Feb. 14, 2005 — -- When it comes to love and companionship in the animal kingdom, sometimes anything goes.

There is the baby hippopotamus who, when separated from his herd, found company in a century-old tortoise at a Kenyan animal sanctuary. The odd pair became inseparable. At another Kenyan sanctuary, a fierce lioness repeatedly adopted young animals she should have been more interested in eating -- oryxes, which are a type of antelope. And a children's book glorified the fine but strange romance between a bull moose and a Hereford cow on a Vermont farm in the 1980s.

If birds of a feather supposedly flock together, what's to explain such odd pairings? In fact, animal behaviorists say they're not as rare as you might think.

"It happens all the time," said David Barash of the University of Washington in Seattle. "I don't think there's anything that truly defies biological explanation."

Take the hippo and the tortoise. While the bond between the animals is certainly unusual, some researchers point out the year-old hippo sought out the tortoise's company only after losing his herd as waters ran dangerously high during the Dec. 26 tsunami in a river that drains into the Indian Ocean.

The hippo, whom park managers called Owen, became dehydrated and was brought to a sanctuary in Mombasa, where he soon found "Mzee," a 120-year-old tortoise who shared little in common with the hippo apart from a dull, grayish color.

At first Mzee hissed at the young newcomer, but soon the Aldabran tortoise was eating and sleeping with the hippo and acting as the calf's mother, even though Mzee is a male tortoise. Owen, meanwhile, treated the old tortoise like a parent, licking his face and following him everywhere.

What could inspire such an odd bond?

"In this case, it sounds like 'any port in a storm,' " said Katherine Houpt of Cornell University's College of Veterinary Medicine in Ithaca, N.Y. "Animals that live in groups are likely to become attached to anything, whether it's a person or another animal. When they're scared, it's more likely to happen."