Lizards do it.  Even fish do it. The animal world is showing us why play is a serious matter. Through a combination of ongoing experiments, reconstructed experiments and guided observation. The Power of Play reveals surprising truths about play in the natural world. Scientists from Europe, the United States and Canada, many of them pioneers in the field, offer convincing evidence that play is not to be taken lightly. In fact, it has the power to make animals and humans smarter, healthier and more likely to survive.