A pregnant Tuarangisaurus is in distress—and her young calf can sense it—as she travels waters that are home to the ocean's deadliest predators.

Above the deserts of North Africa, aerial combat ensues as male Barbaridactylus pterosaurs fight for the attention of females below.

With its feathered body and duck bill, the eight-ton Deinocheirus wades through an Asian wetland in search of relief from pesky biting flies.

Within the snow-covered forest, a tense standoff develops between ancient rivals, Pachyrhinosaurus and Nanuqsaurus.

A journey through an underground cave in North America turns perilous when a young Triceratops is separated from its mother.

On a small island, a monumental display takes place as the giant Hatzegopteryx reveals his gentler side to woo a mate.

Trudging through a scorching desert, two young Tarchia find relief at an oasis and encounter an adult twice their size, ready to lay claim.

In a drought-stricken basin where much has perished, an old Pachycephalosaurus bull defends his leadership against a young challenger.

Deep beneath the water's surface, the world's largest predator—the Mosasaurus—lies in wait to ambush unsuspecting prey.

Not many can intimidate North America's top predator, T. rex, whose size and bite are a deadly combo—except for a giant winged foe.

In a world covered in ice, woolly mammoths and saber-toothed cats fight to survive the coldest temperatures in millions of years.

As sea levels drop and continents shift, animals begin migrating to unknown territories full of new possibilities—and new threats.

With much of the planet's water supply frozen, rock-climbing sloths and marsupial lions must find a way to withstand barren landscapes.

Giant herd animals thrive with the expansion of the grasslands, dominating the plains—but fearsome hunters shadow their every move.

Rising temperatures mean every habitat on the planet is transforming, and for the Goliaths of the Ice Age, the world as they know it is ending.