Penguins are the world's most easily recognized--and perhaps most appealing--group of birds. Flightless, penguins spend the vast majority of their lives swimming in the sea, yet they cannot shake off their evolutionary past: they are warm-blooded air breathers, and they must return to land to lay their eggs. Thus penguins face the challenges of balancing two worlds--the land for breeding, the sea for feeding. This engaging book offers a complete...