Imagine being able to consume 250,000 calories daily without gaining weight. If you had the metabolism of a shrew you could. And while most of us can't hold our breath for more than a few minutes, the Weddell seal can remain underwater for a full 75 minutes! Through many amazing examples this audio discusses the mechanisms humans and other creatures have evolved to gauge their need for food, gather water and oxygen, circulate blood, regulate body temperature, respond to stressful situations, and maintain other survival needs. Download and start listening now!