Games Animals Play

"Happiness is never better exhibited than by young animals, such as puppies, kittens, lambs, and company, when playing together, like our own children," writes Charles Darwin in his 1872 classic, The Descent of Man. Most animals have been observed playing, and play does seem to make them happy. But research has also shown that play is a serious business, and many researchers argue that it has evolutionary significance, essential for developing a host of social, physical, and psychological skills. For instance, Marek Spinka, who studies animal behavior in Prague, and his colleagues have recently argued that play helps animals prepare for the loss of balance they experience when chased by predators, or it can help them deal with the emotions they feel after losing an aggressive interaction. Play, in short, prepares the brain to handle the unexpected.

University of Colorado biologist Mark Bekoff has even suggested that play may contribute to the development of morality. In their playful games, animals can learn about the need for fairness and the consequences of cheating, such as social ostracism. As Bekoff writes in a 2001 article, "During social play, while individuals are having fun in a relatively safe environment, they learn ground rules that are acceptable to others—how hard they can bite, how roughly they can interact‐and how to resolve conflicts. There is a premium on playing fairly and trusting others to do so as well."

Neurological research has also hinted that play may contribute to healthy brain development. Scientists have discovered that rodents placed in environments with running wheels and other play structures show greater brain development than rodents who don't have such opportunities to play. In other words, playing around makes rodents smarter.

This insight has ramifications for humans. Tests on rodents have shown that the mental and physical stimulation they get from playful environments can slow down or delay symptoms of several neurological diseases, including Alzheimer's. Other research has shown that play in rats activates molecules in the brain that can facilitate learning and memory.

Whatever the evolutionary functions of play, we know that birds and mammals do it—and there is even some evidence that reptiles, fish, and insects do it, too. In our tour of the animal kingdom below, we can see how some animal play seems to have a concrete purpose. But other times, animals seem to play for much the same reason humans do: because it's fun.

Horsing around

Baby horses have been observed playing within two hours after birth. They especially enjoy exaggerated galloping and playfully nipping at their mothers during their first days of life. After a few weeks, young horses frolick with other foals and enjoy chasing and circling each other, and tossing around objects like sticks, boards, rags, paper, and buckets. At one month of age, colts and fillies develop different play styles, in preparation for the gender roles they will adopt later in life: Colts spend much of their time playfully fighting and mounting others; fillies, on the other hand, mostly engage in locomotor play, which includes galloping and mutual grooming.