Imagine swimming in the ocean and suddenly spotting a creature larger than any shark, faster than any human can sprint, and more vicious than any predator alive today. Meet the Mosasaurus, a marine ...

Shortly before a mass extinction ended the Age of Dinosaurs, a reptilian, barracuda-like carnivore with a mouth like a box cutter patrolled the warm seas that once covered swaths of what is now North ...

Add Yahoo as a preferred source to see more of our stories on Google. Thalassotitan teeth. Nicholas Longrich Sixty six million years ago, sea monsters really existed. They were mosasaurs, huge marine ...

Plesiosaurs are a group of extinct marine reptiles that lived in the oceans while the dinosaurs lived on land. Find out what plesiosaur fossils have revealed about these animals and how big they could ...

The Loch Ness Monster is perhaps our most famous sea monster, known for drowning locals in front of saints and avoiding motorcycles on its early morning cruise back to the loch. But Scotland’s Nessie ...

An enormous sea snake from Norse legend that was fathered by the trickster god Loki and grew big enough to circle the globe is now the namesake for a different type of “monster” — a newly discovered ...

Scientists have found what may be the world's luckiest Hesperornis — an ancient water bird that escaped the snapping jaws of a plesiosaur about 70 million years ago in prehistoric South Dakota. Still, ...

Bone worms (the red animals in this picture) were first discovered in the early 2000s, but these animals are believed to have evolved more than 100 million years ago. Adapted from Fujiwara et al. via ...

Antarctica was once home to a 10-metre long sea monster that hunted the reptilian equivalent of whales at the end of the dinosaur age, scientists have discovered. The mosasaur, a huge marine lizard ...