It is important to naturally learn how to play from a young age. Imagine a puppy that is only three weeks old. The small furry creature has already begun gnawing, pawing, and tugging at its littermates. At four to five weeks old, its antics rival those of a rambunctious child, chasing and wrestling with its siblings at all hours of the day and night.

Such behavior is not unusual among social mammals. From human children to whales to sewer rats, many groups of mammals and even some birds play for a significant fraction of their youth. Brown bear cubs, like puppies and kittens, stalk and wrestle each other in imaginary battles. Deer play tag, chasing and fleeing from each other. Wolves play solitaire games with rocks and sticks.

However fascinating these displays of youthful exuberance maybe, play among animals was ignored by scientists for most of this century. Biologists assumed that this seemingly purposeless activity had little effect on animal development, was not a distinct form of behavior, and was too nebulous a concept either to define or to study. Even the term “play” caused problems for researchers because it suggests that watching animals goof off is not an activity for serious scientists.

But a steady accumulation of evidence over the past two decades now suggests that play is a distinct form of behavior with an important role in the social, physical, and mental development of many animals. In one study, most animals were found to play the most at ages when permanent changes were occurring in their muscle fiber and the parts of their brains regulating movement. Development at those ages for animals is comparable to that of a two-year-old human infant. At these precise times in the development of animals, muscle fibers differentiate, and it creates the connections to areas of the brain regulating movement. The changes bring about common changes in almost all mammals.

Play may also provide insight into the social development of animals. When the rough and tumble of play ends traumatically with a yelp or a shriek, young animals may be learning the limits of their strength and how to control themselves among others. Those are essential lessons for an animal living in a close-knit group. Perhaps, some scientists guess, as mammals gathered into social groups, the play took on the function of socializing members of the group. Not everyone agrees with this theory, though. Another explanation is that play may not have evolved to confer any advantage but is simply a consequence of higher cognitive ability or an abundance of nutrition and parental care. Why did playing change over time? No one knows for sure, but every baby mammal, even people play at a young age. We play simply for fun.

김우현 강남포스트 학생기자  webmaster@ignnews.kr

<저작권자 © 강남포스트, 무단 전재 및 재배포 금지>