Climate change has an impact on small mammals and some battle to survive. But some others have developed intriguing coping mechanisms to survive.
Rats foul our food, spread disease and damage property, but we know very little about them. A biologist explains how he tracks wild rats in New York City, and what he's learned about them so far.
Plague, one of the deadliest diseases in the world, has been reported in several African countries in the past decade.