The Planets: Inner Worlds

Sixty-six million years ago, an asteroid wiped out the dinosaurs in a fiery global catastrophe. An amazing new trove of fossils reveals how mammals took over, ultimately evolving into the huge array of species, including us, that rule Earth today.

In recent years, an unusual spate of deadly shark attacks has gripped Australia, resulting in five deaths in 10 months. At the same time, great white sharks have begun appearing in growing numbers off the beaches of Cape Cod, Massachusetts, not far from the waters where Steven Spielberg filmed the ultimate shark fright film, Jaws. What's behind the mysterious arrival of this apex predator in an area where they've rarely been seen for hundreds of years? Are deadly encounters with tourists inevitable?

From Yellowstone to the Yukon, to Southern Africa's elephant highways stretching across five nations, explore how newly established wildlife corridors may offer a glimmer of hope to some of our planet's most cherished — but endangered — species.

When the U.S. trade embargo left Cuba isolated from medical resources, Cuban scientists developed their own biotech industry — and promising lung cancer vaccines. Can they now team up with U.S. partners to make the treatments available to all?

What would it be like to go inside the mind of an animal? We have all gazed into a creature's eyes and wondered: what is it thinking about? What does it really know? Now, the revolutionary science of animal cognition is revealing hard evidence about how animals understand the world around them, uncovering their remarkable problem-solving abilities and exploring the complexity of their powers of communication and even their emotions. In this mini-series, NOVA explores these breakthroughs through three iconic creatures: dogs, birds and dolphins.

What would it be like to go inside the mind of an animal? We have all gazed into a creature's eyes and wondered: what is it thinking about? What does it really know? Now, the revolutionary science of animal cognition is revealing hard evidence about how animals understand the world around them, uncovering their remarkable problem-solving abilities and exploring the complexity of their powers of communication and even their emotions. In this mini-series, NOVA explores these breakthroughs through three iconic creatures: dogs, birds and dolphins.

What would it be like to go inside the mind of an animal? We have all gazed into a creature's eyes and wondered: what is it thinking about? What does it really know? Now, the revolutionary science of animal cognition is revealing hard evidence about how animals understand the world around them, uncovering their remarkable problem-solving abilities and exploring the complexity of their powers of communication and even their emotions. In this mini-series, NOVA explores these breakthroughs through three iconic creatures: dogs, birds and dolphins.

From fruit flies to whales, virtually every animal sleeps. But why? Why do we need to spend nearly a third of our lives in such a vulnerable, defenseless state? Scientists are peering more deeply into the sleeping brain than ever before, discovering just how powerful sleep can be, playing a role in everything from memory retention and emotional regulation to removing waste from our brains. So why are we getting so little of it?

Scientists are coming to understand fat as a system akin to an organ -- one whose size may have more to do with biological processes than personal choices. Explore the mysteries of fat and its role in hormone production, hunger and even pregnancy.