Styxosaurus was an elasmosaur, a long-necked variety of the marine reptiles called plesiosaurs. These sea monsters grew upwards of 40 feet (12 meters) long. About half that length was neck ...

When they move on, other marine animals may take up residence in the ... (Learn about the peacock mantis shrimp with your kids.) Not all mantis shrimp boast these spectacular colors.

In fact, marine turtles were the only seagoing reptiles to escape extinction at the end of the Cretaceous, 65 million years ago. A large and pointed head with a sharp beak and strong jaws probably ...

Along the coasts, condors will feed on dead marine animals like seals or fish. These birds do not have sharp predator's claws, but they will raid birds' nests for eggs or even young hatchlings.

Read this story and more in the June 2018 issue of National Geographic magazine ... as a proportion of their body mass than any other marine animal, researchers say: In one large population ...

Box jellies, also called sea wasps and marine stingers, live primarily in coastal waters off Northern Australia and throughout the Indo-Pacific. They are pale blue and transparent in color and get ...

Earth once hosted more than 10,000 species of these ancient marine predators ... chambers separated by thin walls called septa. The animals constantly grew new shell material as they aged ...