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

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.

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

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.