|Plesiosaurs were marine reptiles,
hence they dwelled in the sea. Certain species of Plesiosaur for example
lived close to the shore, where
they could catch prey. One theory is that some Plesiosaurs came to shore
to lay eggs, however their movement on land would have been very limited
and clumsy, similar to present day seals. Unfortunately there is no direct
evidence supporting this theory. It is also believed that Plesiosaurs may
have given birth to live young in the water, similar to present day whales.