Exuberance: The Passion for Life (8 page)

Birds also play. A one-year-old raven at the Zoological Gardens in Copenhagen “quickly learned to throw pebbles, snail shells and a rubber ball vertically in the air, catching them again with great dexterity,” according to one observer. The bird would also “often lie down on its back and shift its playthings from the beak to the claw and back again.” Bernd Heinrich observed ravens drop objects in flight and then swoop down to catch them; the birds also played furiously in the air, with many unnecessary but apparently pleasurable spins and bankings.

Play is conspicuously rare in reptiles, who have little youth to speak of. Usually a reptile gnaws or claws its way out of the egg to find itself only one in a clutch of hundreds, neither sheltered nor protected by its parents and left to its own instinctive devices. For animals subject to the strict metabolic constraints of reptilian life, play is a high-energy, risky, and inessential activity, a luxury to a young animal with limited vitality and restricted thermal resources, vulnerable from birth to tides and predators. Now and again, the predator is one of its own parents. Paul MacLean, a neuroanatomist at the National Institutes of Health, makes explicit an essential difference in the rearing of young reptiles and mammals: “
The young of the Komodo dragon,” he writes, “must take to the trees for the first year of life to avoid being cannibalized, while immature rainbow lizards must hide in the underbrush in order to prevent a similar fate. With the evolution from reptiles to true mammals there appears to have come into being the primal commandment, ‘Thou shalt not eat thy young or other flesh of thine own kind.’ ”

Mammals, as they evolved, spent proportionately more time caring for fewer and fewer offspring. Social behavior and communication took on a commensurate importance. Play, which MacLean and other biologists believe acted originally to promote
harmony in the communal nest, was a critical part of the development of social bonds, communication, and ways of learning how to learn. Through exploration and exchange of sensory information, play introduced an animal to the touch, smell, sound, and sight of others within its own family or species. Such sensory information helped to lay down the tracks of memory and to establish social affinities. These affinities created by play often extend beyond the period of youth: as Marc Bekoff observes, animals that play together tend to stay together. In many instances, play also begins the process of learning how to hunt or forage collectively. Through play, animals learn how to size up the physical attributes of their peers as well, and begin to establish social hierarchies and assess the suitability of other animals for mating purposes. (Once the dominance structure is established in the
communal den of spotted hyenas, for example, aggressive behavior tends to turn more playful.)

Animals also learn through play how to curb their aggressive instincts toward others of their own kind. The pleasure of play reduces the chance of inflicting serious injury on those who have shared in it. Beavers, for example, are highly social animals that form intense family bonds. Hope Ryden, who for four years studied a family of beavers living in a lily pond in New York State, was initially incredulous that large families of beavers, sometimes as many as fourteen, could survive throughout a winter sharing cramped living quarters and depending upon food from a common stockpile. To do so, she reasoned, the animals had to have highly complex social strategies allowing them to communicate in subtle ways, extensive sources of mutual and communal pleasure, and, above all, a high threshold for the release of aggressive behavior. Throughout much of the year, Ryden noted, beavers did in fact build up strong social bonds through pleasurable nibbling and grooming of one another, close physical proximity, and extended periods of ebullient play.

“How do beavers keep from getting on one another’s nerves?” she asks in
Lily Pond
. “
Not a single night had passed but I had watched my beavers swim alongside one another, or touch noses, or ‘speak’ to one another. And how often had I seen two or more of them seek one another out for no other reason than to feed in company? Yet the lilies they consumed side by side were available all over the pond. And what of the precision diving and porpoising bouts I had witnessed? Were these not expressions of exuberant play? [The beavers] engaged in nonstop aquabatics, plunging under and over each other, swimming together and down. Suddenly, up again. First one, then the other, rolling, porpoising, somersaulting. This was exuberance.” Nature, Ryden concluded, had given the beavers strong social glue; fast-held pleasures kept their aggression at bay. Exuberance bound beaver to beaver into a close and united group.

Exuberant play appears to be particularly important in nourishing social affinities in very young animals that later become members of a cohesive social unit.
Wolves, who form close packs as adult animals, show more playful behavior when young than do coyotes and red foxes, who grow up to be more solitary.
Common seals engage in highly exuberant play when young; as adults they form tightly cohesive social groups and display little evidence of fighting or aggressive competition for mates. Grey seals, on the other hand, are much more likely as adults to disperse along a shore than live together in closely bound groups. They are also less likely to vigorously play together as pups. It is not just the amount of contact that is important, however, but the nature of that contact. The ethologist Desmond Morris has suggested that exuberant movements during play may have a “catalytic” effect on the formation of social affinities and that these bonds would not be so strong if the young seals “
merely nuzzled each other in a tranquil manner.”

Play is critical in diffusing social tensions as well. The naturalist
Benjamin Kilham, who rears orphaned wild black bear cubs, recounts an occasion when, after a week had elapsed during which he could not spend time playing with the cubs, one of them “slow-bit” his hand with a canine tooth. “
Something was obviously amiss between us, so … I took them on a walk. But even that was abnormal and strained. Reluctant even to start out, the cubs moved slowly along behind me, feeding on beechnuts for a while before following me up the hill toward a bear tree. Halfway up the hill they sat down, so I joined them. Then they decided to play … a twenty-minute roughhouse session ensued. Afterward I took a half-hour nap entwined in an ursine mass. Everything was back to normal.” Play was restorative to the temporarily disrupted social bonds.

Elephants are particularly known for their tight social bonds and for an extended period of maturation. The young suckle for four years, and births are few and far between. Each young calf represents an enormous investment of time and energy by its mother and others in the close-knit community. Cynthia Moss, who directs the Amboseli Elephant Research Project in Kenya, describes the family reaction to the birth of an elephant calf as “
almost delirious with excitement.” There is, she says, much screaming and trumpeting and communal expression of joy. These intense emotions “are part of what they are doing right. They are the glue that keeps the families together.”

Joyce Poole, like Cynthia Moss, has studied African elephants for decades. Expressions of joy are frequent in elephant families, she observes, especially when they greet one another after having been apart. The “greeting ceremony” may involve as many as fifty elephants and occurs after elephants have been separated for as short a period as a few hours or as long a time as several weeks. The greeting, Poole writes, is “pandemonium.” The elephants “
rush together, heads high, ears raised, folded, and flapping loudly, as
they spin around urinating and defecating, and secreting profusely from their temporal glands. During all this activity they call in unison with a powerful sequence of low-frequency rumbles and higher frequency screams, roars, and trumpets.” Poole believes, as other elephant researchers do, that the joy female elephants feel when they reunite is part of a response essential to their survival. Calves born into large and closely united families are more likely to survive, and strongly shared positive emotional responses reinforce the social bonds within those families. Elephants, Poole observes, are raised in “an incredibly positive and loving environment.” She says she has never seen a calf disciplined: “
Protected, comforted, cooed over, reassured, and rescued, yes, but punished, no.” As Cynthia Moss has put it, “
elephantine joy plays a very important role in their social lives.”

Play and other exuberant social behaviors also have a contagious effect. Moods are by nature infectious, and joyous moods tend to spread rapidly throughout a group or herd of animals, heralding as they go that it is safe to enjoy, rest, hunt, explore, or play. Adelie penguins in the Antarctic, for example, exhibit an “ecstatic display” when they return to their colony: “
The bird suddenly stretches its head and bill upward,” writes one observer, “and then, with rhythmic beats of its flippers and its head still pointing to the sky, slowly emits a [sound] not unlike the slow roll of a drum.” The behavior, which is repeated over and over again, is highly contagious, spreading from bird to bird throughout the community. As many as a hundred thousand birds have been observed taking part in this display.

Sometimes contagious exhilaration is preparatory to a group activity that requires both social cohesiveness and physical risk or exertion. This is certainly true for many human activities, as we shall see, but it also occurs in other mammals. Prior to a hunt,
African wild dogs will gather together, sniffing one another and
bounding about in energetic play. As time goes by, the playing gets wilder and rougher, finally reaching a climax when the whole pack masses together and then sets off after a gazelle or wildebeest. Field biologists who have observed this play-then-hunt behavior contend that the progressive buildup of excitement before hunting looks like “nothing so much as a ‘pep rally,’ that serve[s] to bring the whole pack to hunting pitch.”

Social play in rats, which occurs after weaning but before sexual maturation, is critical to the development of their social and cognitive skills. Play behavior in these juvenile rodents, not surprisingly, is highly rewarding to them and has been shown to be regulated by the
powerfully reinforcing opioid systems in the brain. Drugs that block these opioid systems reduce the urge to play. Behavior patterns laid down during the early weeks or months of intensive play are of lasting importance not only to the individual animal but to other animals in its social network. Play, which the neuroscientist Jaak Panksepp has described as the “
brain source of joy,” is thought to be tied to a variety of other beneficial physiological responses as well, including strengthening the immune system and increasing resilience under stress.

Panksepp believes that
play probably increases gene expression in the frontal lobe for a protein involved in brain development. Experimenters have also shown that mice raised in cages filled with tunnels and toys play more, explore more, and ultimately generate more new neurons than mice raised in standard cages. Extensive psychological research in humans, to which we shall return, shows a highly beneficial effect of positive mood on learning and flexibility in thinking, in addition to its significant influence on social behavior. Play is the headwater of this elated, shaping mood.

We tend, as a thinking species, to emphasize the beholdenness of our emotions to our thoughts, rather than to trace our thinking to the ancient powers of our emotions. Yet our emotions were laid
down far earlier than language or imaginative thought, sculpted by the realities of survival that we share with all other animals: to explore and to know our territories, to stay out of the grasp of our predators, to scavenge food and mate, and to set up safe havens. Each requires the complex yoking of swift and intense emotion to physical agility and, increasingly, with the evolution of higher animals, to mental acumen. Survival depends on comprehending the elements of the environment and then acting effectively upon that comprehension.
Trout raised in hatcheries, for example, have smaller brains than trout born in the wild, who must learn to recognize and evade predators and to spot, chase, and capture prey. Charles Darwin had observed this more than a century earlier. “I have shewn,” he wrote in
The Descent of Man
, “that
the brains of domestic rabbits are considerably reduced in bulk, in comparison with those of the wild rabbit or hare; and this may be attributed to their having been closely confined during many generations, so that they have exerted their intellect, instincts, senses, and voluntary movements but little.” To explore further is to learn more, and to learn more is to acquire the means of dealing with an unpredictable and changing world. Play promotes and encourages this.

Play helps the animal acquire knowledge about both the potential and the dangers of its world; it sets and becomes the physical arena for exploring new objects and for combining physical activities with sensory experiences in ways that might otherwise remain untried. Play increases the scope of the animal’s experience and the range of its skills, generates a greater sense of control, and allows the animal to test its competence. Jane Goodall has emphasized the central role of play in making young chimpanzees familiar with their environment. The young ape, she writes, “
learns during play which type of branch is safe to jump onto and which will break, and he practices gymnastic skills, such as leaping down from one branch and catching another far below, which when he is older will
serve him in good stead—during an aggressive encounter with a higher-ranking individual in the treetops, for instance.” The young chimps, in short, learn to go out on a limb.

Behavior that expends such energy, that is potentially dangerous yet intensely reinforcing, and that is nearly universal in the more cognitively complex animals must be of consequence. Play is unscripted. In being so, it introduces and rewards flexibility, prepares the animal for the unpredictable, and makes enjoyable the animal’s testing of the boundaries of what it knows and what it has yet to know. Play is about learning how to learn. It is a kind of controlled adventure, an exploration of both new and familiar worlds. Play and curiosity are inevitably linked.