Animals Just Want to Have Fun, Survey Finds

May 11, 2009 -- From tickling to playing catch, animals engage in certain behaviors just for fun, even enjoying sensations that are unknown to humans, concludes an extensive new survey on pleasure in the animal kingdom.

The findings, published in the latest Applied Animal Behavior Science, hold moral significance, argues author Jonathan Balcombe. He believes scientists, conservationists and other animal rights activists should not overlook animal joy.

View a slide show about animals seeking pleasure here.

"The capacity for pleasure means that an animal's life has intrinsic value, that is, value to the individual independent of his or her value to anyone else, including humans," Balcombe, a senior research scientist for the Physicians Committee for Responsible Medicine, explained to Discovery News.

He determined animals experience happiness for happiness' sake related to play, food, touch and sex. Observations of herring gulls in Virginia, for example, found these birds play "drop-catch," tossing clams and other small, hard objects as though they were baseballs, just for pure enjoyment.

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In terms of food, green iguanas go to great lengths to find fresh, leafy lettuce, even when supplied with ample amounts of more nutritious reptile chow. Studies on other animals indicate some foods, independent of their nutrition levels, cause animals to release pleasure-producing opioids in their bodies. Language-trained apes and parrots have even told their owners they loved or hated certain edibles.

Pleasure itself can be the end-all reward, as "regardless of the evolutionary benefits of a behavior," he said, "animals often do things because they are rewarding."

"I doubt that a monkey thinks, 'If I eat this fig it will sustain me,' but rather, 'Ooh, yummy, a delicious fig!'" added Balcombe, whose book "Exultant Ark: A Pictorial Tour of Animal Pleasures" is scheduled for release next year.

Regarding touch, a human might go to a spa for a mud bath and massage, but nature creates its own "spas" for hippopotamuses at freshwater springs in Kenya. There, wallowing hippos gather, moving in and out of "cleaning stations" where multiple fish species congregate to nibble hippo parasites, loose skin, fungal growths and more.

The hippos "deliberately splay their toes, spread their legs and hold their mouths open," often becoming "so relaxed during these spa treatments that they would sometimes fall asleep," Balcombe recounted.

Sex isn't just for procreation, the paper further suggests.

"Oral sex that appears purely for pleasure has been documented in goats, hyenas, various primates, manatees, bats and sheep," said Balcombe, who added that homosexuality is practiced within at least 300 species. Masturbation, even among certain birds, has also been noted.