The lush riverside vegetation sways as a herd of elephant wends its way between the broken pools. Standing at the top of an embankment, a half-grown male is watching a larger elephant trudge up the slope toward it.
Without warning, the youngster squats down on his haunches (just like a dog) and launches himself down the slope. Slithering at a good speed, he collides (with an audible thump) into the elephant below, sweeping them both, in a flurry of waving limbs and trunks, to the foot of the hill. There, lying on their stomachs, the pair jousts, twisting and parrying with trunk and tusk.
Meanwhile up above, an onlooker waits, scuffing his feet impatiently and swinging his trunk from side to side. He seems to be waiting for them to clear the trail, but when the two finally begin to traipse up the slope, he squats and whooshes down to create a three-elephant pile up. What these elephants are up to is a mystery.
Everyone knows that young animals play to prepare for adulthood But as far as science is concerned, there’s not one iota of evidence to support these myths.
There is evidence that play does help animals to survive and breed.
Long-term research on American brown bears has revealed that cubs who romp a lot are more likely to survive to independence, even after taking into account the cub’s (and its mum’s) condition, and the availability of food (15).
extra playful individuals go on to make better mums, rearing more little ankle-biters in their first breeding season (13).
Plunk two little rats together and it’s almost impossible to stop them whooping it up. But thwart a young rat’s zeal for play (by rearing it alone or with drugged companions that won’t play) and you create an adult that loses its cool in social situations.
When things start getting edgy, play-deprived rats either succumb to rat-rage or scarper, quaking, to a corner. And the lack of play is responsible, because if you let an isolated rat fool around for just one hour daily, it turns into a normal chilled dude (16).
And there’s also evidence that primates (including humans) behave in the same way (17, 18).
So does merrymaking teach young critters how to read the intentions of others (19)? Or perhaps it boosts their confidence by letting them experience winning and losing in a non-threatening way (20)? I have to admit that if I had to put money on it, I’d go for the theory about stress.
I still think part of it is about training and practising skills.
You see when a baby animal experiences stress, its brain changes so that it’s subsequently less sensitive to stress hormones. This means that, as an adult, the critter recovers more rapidly after a hair-raising experience (21). And we know that play (which normally consists of exciting ‘flight or fight’ behaviors) activates the same neurochemical pathways as stress (22). So maybe young animals are using play to prime or fine-tune their own stress response.
The other very important thing we’ve learnt from the humble rat is that when they’re reared with lots of companions and interesting objects, they develop larger brains than rats that grow up in austere surroundings. These enriched rats not only have heavier cerebral cortexes, with more neural connections, they learn more quickly too.
Researchers teased apart the factors that promoted this brain growth and found that sensory stimulation and arousal (even together) couldn’t increase cortical growth unless they were coupled with interactive behavior (i.e. play or training). And it was play that had the biggest impact; in fact, the more a young rat played, the more rapidly its brain grew (23).
So it turns out that fun isn't just about training for becoming an adult it makes you live longer through being less stressed and being able to cope with stress better.