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 ...

Sixty six million years ago, sea monsters really existed. They were mosasaurs, huge marine lizards that lived at the same time as the last dinosaurs. Growing up to 12 metres long, mosasaurs looked ...

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 ...

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 ...

Fossils of a giant killer mosasaur have been discovered, along with the fossilized remains of its prey. At the end of the Cretaceous period, 66 million years ago, sea monsters really existed. While ...

Nicholas R. Longrich does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations ...