Why Elephants Have Big Ears: Understanding Patterns of Life on Earth

This book might have been titled On the Perfection of Crocodiles. Chris Lavers, a biogeographer at the University of Nottingham, argues that "After 200 million years of hegemonic ecological success, it is time to recognize crocodilians for what they truly are: perhaps the closest approximation to an unsurpassable ecological design in the entire history of tetrapod life." There's a reason, he shows, that "alligators are as tough as old boots": it's not necessarily better to be warm-blooded. "If the warm-blooded condition were inherently superior in the struggle for life, then the world would be crawling with mammal-like and bird-like creatures, whereas in truth it is quite literally crawling with lizards, frogs, snakes, spiders, and beetles." Lavers looks around the animal world and points out that it's full of large warm-blooded creatures and many, many more small cold-blooded ones.

"There is a natural order to tetrapod life on our planet, rooted in the natural ecological talents of different types of animals," Lavers writes. These natural talents come from the fundamental characteristics of different forms and metabolisms: cold-blooded animals like crocodiles can endure starvation far better than warm-blooded creatures, while warm-blooded ones, if properly fueled, can keep going under conditions that stop crocodiles, well, cold. Biologists are used to thinking that energy balances, costs, and benefits are fundamental issues for living creatures, but not of thinking that these issues can be interesting to the general public. Lavers shows that they can be perfectly fascinating: he writes of the peculiarities of elephants, of hot and cold running dinosaurs, of birds on the wing and the ground, with verve and accuracy. This book might be a particularly good choice for dinosaurophiles who are looking to broaden their interests to even larger patterns of life on Earth. --Mary Ellen Curtin