A long-necked plesiosaur hunts a shark in shallow waters


Plesiosaurs were long-necked marine reptiles, closely related to the Pliosaurs though probably slower in the water. Their swimming speed has been estimated at 8.2km/h, which is faster than an Olympic champion, but too slow to catch a mackerel, salmon or seal. Plesiosaurs are often depicted with their neck bent into sinuous folds. In truth it was not that flexible, and no Plesiosaur ever bent its neck into the tight curve today's swans can manage. Plesiosaurs became extinct at the same time as the dinosaurs.

Scientific name: Plesiosauroidea

Rank: Suborder

Common names:

near, close to lizard

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The following habitats are found across the Plesiosaurs distribution range. Find out more about these environments, what it takes to live there and what else inhabits them.

Shallow seas Shallow seas
Shallow seas cover the continental shelves. These sunlit, or neritic, waters are where the oceans are most productive, where biomass is highest and where all the major sea fisheries of the world take their catches.


Discover what these behaviours are and how different plants and animals use them.

Additional data source: Animal Diversity Web

When they lived

Discover the other animals and plants that lived during the following geological time periods.

What killed them

Cretaceous-Tertiary mass extinction Cretaceous-Tertiary mass extinction
The Cretaceous-Tertiary mass extinction - also known as the K/T extinction - is famed for the death of the dinosaurs. However, many other organisms perished at the end of the Cretaceous including the ammonites, many flowering plants and the last of the pterosaurs.


  1. Life
  2. Animals
  3. Vertebrates
  4. Reptiles
  5. Sauropterygia
  6. Plesiosauria
  7. Plesiosaurs

BBC News about Plesiosaurs