Plesiosaurs were creatures with flippers, long necks and a small head. They were all reptiles and many think they had pups/calves in the water, like whales, dolphins, etc. do today.
Plesiosaurs breathed air through nostrils and would have had to surface for air, like whales, dolphins, etc do today. Some think that, with their long necks, they could swim in the water and have their nostrils and/or head out of the water to breathe. No proof for this theory has stepped forward.
As far as can be gathered, it seems plesiosaurs had a smooth skin like a dolphin or a seal instead of scales like most reptiles. Perhaps plesiosaurs were covered in blubber to to keep themselves warm, we just won’t know until we see a live one.
These creatures were short-necked and had gigantic heads compared to the small-headed plesiosaur. In fact, some pliosaurs . . . go read the rest of the article >>