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Top 7 Quirky Facts About Plesiosaurs

Jana loves unusual history. She strives to share the bizarre and funny cases of yore with kindred spirits.


Plesiosaurus Facts

Plesiosaurs were the oddballs of the sea. They resembled a cross between a dolphin and a crocodile while balancing tiny heads on giraffe-like necks. Despite the Frankenstein factor, these carnivorous reptiles once owned the oceans and they left behind fascinating facts!

1. They Were Great Moms

Researchers now believe that the creatures shared a trait with another aquatic reptile. Similar to crocodile females, plesiosaurs were likely doting mothers. This suspicion is an old one, mainly because plesiosaurs were too big to drag themselves to the shore and lay eggs like a turtle.

But the proof that plesiosaurs gave birth to live young was only recently discovered. A fossil of a pregnant plessie turned up and she was carrying a single, large baby. This was another sign that the species was blessed with good mothers. Most marine animals that bear single young in modern times often provide years of care to their offspring. Plesiosaurs infants probably received prolonged parental care after birth as well.

2. They Had Back Problems

In 1970, paleontologists found something rare — a fossil with disease. Usually, ancient bones show scars, breaks and teeth marks. But to find illness in a fossil is exceptional. In this case, scientists were examining the spine of a plesiosaur when they discovered lesions from a spinal condition known as Schmorl’s nodes. The animal had it bad, 24 of its 27 vertebrae were affected.

Schmorl’s nodes is a common disease in humans. However, finding it in a plesiosaur was a unique situation. This was the first case discovered in any aquatic animal, reptile, or non-human for that matter.

One can imagine that their long necks played a role in spine-related problems. The incredible length probably placed a lot of stress on the bones.

3. A Gem Called Eric

In life, Eric was a pliosaur. They were closely related to plesiosaurs but had shorter necks. When he died something remarkable happened. The animal turned into the semi-precious gemstone known as an opal. There was even an opal fish inside his stomach.

The 7-foot find was unique but the owners of the opal mine were unimpressed. They planned on selling Eric as raw material to jewellery makers. Palaeontologists fought to save the fossil and a public campaign raised enough funds to purchase Eric. Today, he is safe and sound at the Australian Museum.

Eric's neck bone

Eric's neck bone

4. The Loch Ness Bones

Loch Ness in Scotland is said to harbour a monster. Eyewitnesses described the creature and before long, people realized that Nessie looked like a plesiosaur. Some monster fans now believe that Loch Ness Monster sightings are glimpses of a surviving population of plesiosaurs.

There is an interesting twist to this story.

One day, a pensioner strolled along the shores of Loch Ness when he found bones. They belonged to a plesiosaur. For believers, this was evidence that plesiosaurs had managed to survive at the Loch. But sadly, the bones were not new. This particular plesiosaur had died 150 million years ago. Loch Ness only formed 12,000 years ago.

5. They Flew Like Penguins

Since the first plesiosaurs were discovered decades ago, their locomotion was like palaeontologists' dandruff (it made them scratch their heads a lot). Nobody could figure out how these creatures moved their big bodies through the water.

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With the advent of better software, the mystery was solved. Scientists took everything they knew about the animals and fed the data into a program. The program was designed to reveal the likeliest swimming style of plesiosaurs but instead, it erased any chance of a swimming style.

The program revealed that the ancient giants did not swim. The hind flippers were close to useless and contributed nothing to the animal's speed. Then how did they move? The carnivores flapped their front flippers and literally flew underwater like penguins do today.

Powerful paddles

Powerful paddles

6. They Snacked on Birds

A whopping 70 million years ago, a sea bird almost became dinner. This story would have been lost in time had its skeleton not ended up in a museum. When researchers looked at the leg bone, they found bite marks. Signs of infection and healing showed that it survived the attack.

To find the attacker, researchers looked at all their meat-loving fossils. The only teeth that fit the bite on the bird came from the skull of a juvenile plesiosaur.

The find was a game-changer. Marine birds were not considered a part of the plesiosaur diet. But the bone strongly suggested that the reptiles ate birds when the opportunity presented itself. Perhaps, in this case, the bird was bobbing on the surface of the ocean and the young plesiosaur grabbed it by the leg.

7. The Plesiosaur Puzzle

In 2014 an amateur palaeontologist named Jonathan Bow found a skeleton. It was the biggest fossil ever discovered in Wales. Unfortunately, when he tried to move it, Bow accidentally broke the 200-million-year-old reptile (ironically, it shattered into 200 pieces).

Did he run away and pretend it wasn't him? Nope. He spent the next two years glueing the giant back together. The species, Avalonnectes, is also now Wales' most complete plesiosaur fossil. This guy deserves a medal.

Questions & Answers

Question: Were plesiosaurs dinosaurs?

Answer: Plesiosaurs were not dinosaurs. They were an incredibly successful group of marine reptiles that first appeared during the Triassic period about 200 million years ago.

© 2019 Jana Louise Smit


Jana Louise Smit (author) from South Africa on February 23, 2019:

Agreed, Stan. They have a special, almost otherworldly vibe that's very magnetic. A pity we don't have a few running around anymore! :)

Stanley Johnston on February 23, 2019:

Interesting. Ive been intrigued by dinosaurs since I was a kid.

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