Big cat populations are shrinking fast, but now we have the means to view them in more detail than ever.

Join filmmaker Casey Anderson as he embeds in the Alaskan wilderness to follow the largest terrestrial carnivores in the world.

By examining countless Megalodon teeth from around the world, scientists have concluded that "meg" was able to achieve its gargantuan proportions by starting its carnivorous diet early -- in the womb.

New research reveals how incredible these ancient, unchanged reptiles really are - partly because of what’s called negligible senescence. This means that Alligators show almost no signs of aging -- regardless of how long they live - and that they are “biologically immortal.”

El León es conocido como el Rey de la Selva. Pero fueron los tigres dientes de sable los que gobernaron las Américas en el pasado. Sus fósiles nos cuentan la vida violenta y casi humana de esta misteriosa especie.

It’s the dry season near the Serengeti and hungry lions threaten the livelihood of cattle-herder Rugari and his family. He could kill the predatory lions and protect his cattle, but his daughter seeks another solution. Filmed on location in Tanzania—where the worlds of lions and humans collide.

Dan O’Neill is on a mission to find, film, and measure the biggest living crocodiles. Dan joins Dennis, an indigenous saltwater crocodile guide in Australia’s Northern Territory, hoping to track down a legendary giant male lurking somewhere along the Mary River.

New discoveries of dinosaur fossils are completely changing what we know about the animals that lived on our planet millions of years ago.

Journey back to primeval Earth in the age of dinosaurs for new findings and puzzling discoveries about their evolution and extinction.

Wiped off the face of the Earth by humans nearly a century ago, geneticists are now working on resurrecting the enigmatic Tasmanian Tiger.

Great white sharks are one of the most feared predators on Earth, and yet we know very little about them. Science is now revealing the mysteries of this perfect predator through evolutionary biology.

In this unprecedented series, recent scientific discoveries shed new light on the extraordinary prehistory of big cats.

Capture teams from the U.S. National Park Service track down and relocate wolves to Isle Royale National Park in Lake Superior under an ambitious initiative to restore balance to a wilderness ecosystem.

The Tyrannosaurus Rex is known as the king of the dinosaurs, but how did its reign begin? Meet Moros Intrepidus, a 180 lb., deer-sized ancestor to the T-Rex. Learn how the latest in paleontology can now link this small dinosaur to the 19,000-pound Scotty, the largest T-Rex ever discovered.

A cheetah raises her young family on the vast expanse of the Serengeti, facing enormous challenges. Lions are quick to throw their muscle around, and hyenas and jackals attempt to steal anything the cheetah manages to kill. The cubs will have to learn fast if they're going to survive.

The crocodile is the king of the wetland; a tone of a cold-blooded monster with the most terrifying bite force on Earth. The product of a 100 million year ancestry, the 25 species around today are a testament to the crocodile’s supreme intelligence and adaptability.

The endless plains of East Africa is a paradise for lions. The most social of all cats, lions form prides that are unlike any other animals. Together, they’ll hunt, raise their young and defend their territory. The pride welcomes new babies every year, but new children bring new dangers.

The ghost cat is one of the most elusive animals roaming the wilderness. Adaptable and resilient, these cats dictate a precarious cycle of life for the creatures who share their home. In the cold, inhospitable mountains above Chile, a single mother raises her three cubs.

T-rex -- the "tyrant lizard king" -- ruled the earth 65 million years ago. Today, he reigns as ultimate predator and pop cultural icon. His image is everywhere -- but few know how two scientific rebels probed the mystery of his sudden death, and uncovered the day that shaped the modern world.