Analysing The Skeleton: The Plesiosaur Diet

Updated Tuesday 24th August 2004

Palaeobiology - a look at the evidence of the diet of plesiosaurs

Functional analysis of the jaws and teeth

We can also look at the jaws and teeth to learn about the diet of plesiosaurs. Pliosaurs with their massive heads and throats could eat large prey. They were not fussy eaters! Their heads and jaws were also very strong allowing them to clamp onto large prey with big deep-rooted teeth and then twist off lumps of flesh by rolling their whole body! These pieces would be of suitable size to be swallowed whole. This method of feeding is called twist feeding and is used by crocodiles. Isolated fossil bones are often found that may have been dropped by the pliosaurs during twist feeding. The teeth of some pliosaurs are unusually curved backwards, suggesting they were used to pull struggling prey into the mouth.

Functional analysis of the body

Because you must catch your meal before you can eat it, swimming speed is important for aquatic carnivores. By measuring the shape of the body, and other properties of the body that affect swimming, the speed for plesiosaurs has been estimated. Long necked plesiosaurs were estimated at 5.1 miles per hour, the speed of a slow ambush predator, and pliosaurs were slightly faster, indicating that they chased their prey rather than ambushing it.

Lookalikes - using living animals

Similarities between the teeth of marine reptiles and modern large marine carnivores provide us with clues as to the diet in extinct marine reptiles. Today killer whales (Orcinus orca) eat large mammals such as seals, sea lions and dolphins. Their teeth show many similarities with pliosaurs so they are likely to have relied on similar prey. Of course, there were no mammals then, so they must have eaten similar sized animals that were about then, such as ichthyosaurs and marine crocodiles. The teeth of plesiosaurs show similarities with the piscivorous (fish eating) gharial, also known as the gavial, a long-snouted crocodile. Both of these animal's teeth interlock, so plesiosaurs probably ate fish too.

A meat eater is not always a predator

Being a meat eater (carnivore) does not necessarily mean an animal was a predator. Stomach contents containing dinosaurs provide evidence that pliosaurs scavenged dinosaur corpses that floated out to sea. This is also evidence that large pliosaurs were opportunistic, eating whatever they came across. Cryptoclidus, a common plesiosaur in Britain during the Jurassic, had many thin needle-like teeth and may be similar to the living crabeater seal, which has sieve-like teeth for capturing krill, small shrimp-like organisms. A 'rushing upwards' style of attack is inferred for large pliosaurs like modern great white sharks, because this is an efficient way for large animals to hunt.

Combining the evidence

By combining all this evidence, we have been able to build up a picture of exactly what plesiosaurs ate.

Next: The riddle of the stomach stones


For further information, take a look at our frequently asked questions which may give you the support you need.

Have a question?

Other content you may like

Monitoring polecat populations using roadkill Creative commons image Icon 'Velvet' / Peter Trimming / CC BY 2.0 under Creative-Commons license article icon

Nature & Environment 

Monitoring polecat populations using roadkill

Are polecat populations growing? One way to check is to survey numbers of polecats live and dead on the roads

The Greenland white-fronted goose Creative commons image Icon Greenland White Fronted Goose / Hilary Chambers / CC BY-ND 2.0 under Creative-Commons license audio icon

Nature & Environment 

The Greenland white-fronted goose

Waterfowl expert Tony Fox talks to Saving Species about a goose that has been on conservation concern for many years.

15 mins
The science of evolution Copyrighted image Icon Copyright: Used with permission free course icon Level 1 icon

Nature & Environment 

The science of evolution

This free course debates the issues surrounding the science of evolution and religion.

Free course
5 hrs
Defying Death Copyrighted image Icon Copyright: Used with permission article icon

Nature & Environment 

Defying Death

This extract explores issues about improvements in health care, and our expectation of a longer life. It is taken from a panel discussion that took place as part of 'The Next Big Thing' TV series.

article icon

Nature & Environment 

What Did The Bristol Dinosaur Look Like?

Palaeobiology - what the Bristol dinosaur might have looked like

Weaver bird nests Creative commons image Icon The Open University under Creative Commons BY-NC-SA 4.0 license video icon

Nature & Environment 

Weaver bird nests

Dr Dieter Oschadleus explains how and why weaver birds build their nests the way they do.

Society and genetics Copyrighted image Icon Copyright: BBC article icon

Nature & Environment 

Society and genetics

Dr Gerry Mooney, staff tutor in Social Sciences at the Open University in Scotland, assesses the effect that genetic testing may have on society.

Protecting the Spectacled Eider Creative commons image Icon usfwsendsp under CC-BY under Creative-Commons license audio icon

Nature & Environment 

Protecting the Spectacled Eider

The Saving Species team talks to Matt Sexson from the University of Alaska about his work studying the spectabled eider, an endangered sea duck

15 mins
Sacred forests Copyrighted image Icon Copyright: Jupiter Images audio icon

Nature & Environment 

Sacred forests

Martin Palmer is from the Alliance of Religions and Conservation (ARC). He is joined by the Saving Species team to explore the role religion can play in conservation

15 mins