Extras

Video thumbnail: Nature Are lions the most intelligent cat?

Nature

Are lions the most intelligent cat?

Dr. Natalia Borrego works with lion whisperer Kevin Richardson to carry out lion IQ tests.

Are lions the most intelligent cat?

Video thumbnail: Nature The Truth About Tiger Populations

Nature

The Truth About Tiger Populations

Like so many other wild cats, survival of the tiger is on a knife edge.

The Truth About Tiger Populations