By Anya Haigh
Plesiosaurs were around four metres in length and as you can see from their very sharp teeth, they were carnivores which means they only ate meat such as squid and fish.
VOTE NOW for Plesiosaurs in our Jurassic Coast Big Five competition
Top Three Fascinating Facts
- Did you know that even though Plesiosaurs look like dinosaurs they weren’t actually dinosaurs! They were in fact ancient marine reptiles that happened to live alongside the dinosaurs throughout the Triassic, Jurassic and Cretaceous. They were most common in the Jurassic over 150 million years ago! [2]
- Plesiosaurs were very strong swimmers. This meant that they could swim all around the world. They were able to survive the end Triassic mass extinction that happened 200 million years and wiped out over 70% of all species on earth! They finally became extinct 66 million years ago alongside the dinosaurs. [3] Even though they spent all their time in the sea they didn’t have gills like fish so they would have had to have come to the surface to breathe.
- Plesiosaur necks made up around half of the animal’s entire body. In their neck they have been found to have had over 70 individual vertebrae (small bones that make up the spine) which is over 10 times the number that we have! As Plesiosaurs were marine creatures it was very important to be streamlined which lead to their neck being rather stiff to help with this. [4]
A plesiosaur fossil found by Mary Anning
A Surprising Fact
Plesiosaurs gave birth to live young, a bit like us humans. They would only have had one baby at a time as the baby would have been up to 1.5 metres before it was even born. This means that it would have been up to a third of its mother’s size before it even started eating live food! [5]
Researchers think that because of the massive effort it would take to give birth to just one baby it is likely that the baby would have stayed with its mother for some time after it was born and may have even lived in pods like whales do today. [5]
Why you should vote for Plesiosaurs
Two of the very first nearly complete Plesiosaur fossils were found right here on the Jurassic Coast by Mary Anning in the 1820s [6]. This was a revolutionary find and led to one of the first correct identifications of the group. Plesiosaurs have a deep history rooted in Dorset and Devon, and have been found all along the Jurassic Coast for many years.
References:
1. https://oumnh.ox.ac.uk/out-of-the-deep
2. https://www.bbcearth.com/walking-with-dinosaurs/modal/plesiosaurus/
3. https://www.newscientist.com/article/2156370-this-is-the-oldest-fossil-of-a-plesiosaur-from-the-dinosaur-era/
4. https://www.nationalgeographic.com/science/2019/06/fossil-sea-monster-found-antarctica-heaviest-of-its-kind-elasmosaurs/
5. https://www.nationalgeographic.com/news/2011/8/110811-plesiosaurs-live-birth-fossils-young-science-chiappe-dinosaurs-fetus/
6. https://en.wikipedia.org/wiki/Mary_Anning#Plesiosaurus