Dinosaur Files

What wiped out all the sea-faring dinosaurs?

I wonder what wiped out oceanic dinosaurs like the Plesiosaurs? Some claim large asteriods might have wiped out land dinosaurs, and that the ice age might have wiped out sea dinosaurs. That doesn't seem right to me, since turtles survived, as well as prehistoric fish such as the Coelacanth? The sea seems to have plenty of food living at various depths - so what is the most plausible suggestion as to why some early animals survived, while plesiosaurs and other aquatic dinosaurs did not?

Public Comments

1. I've wondered that myself. I'd guess food supply and evilution and mutations? but remember that even pristoric versions of animals today where diffrent and the turtles where most likly used to cold waters.
2. Most people think that after the initial disaster- asteroid strike- the food chains were severely disrupted. So animals higher up the food chain were the most vulnerable. Undernourished animals are more susceptible to sickness and so add to the death rate. The beneficiaries of such circumstances are scavengers of all sizes, microscopic or big animals. If they can survive the environmental changes they are suddenly in an ideal environment, lacking predators and having more food then usual. Turtles are pretty tough animals and many are both predators and scavengers at the same time. Deep sea fish are the least exposed to changes in light and temperature, at depth the change is little.
3. Just a correction, there are no sea faring dinosaurs. The animals you are referring to are extinct marine reptiles, they are not closely related to dinosaurs (pterosaurs are not dinosaurs either).
4. There were no sea-faring dinosaurs. Dinosaurs were an exclusively land-living group - they did not fly (like pterosaurs) or live in water (like plesiosaurs, mosasaurs or ichthyosaurs). The Earth was undergoing a period of climate change at the time the dinosaurs, large aquatic reptiles and flying reptiles all became extinct. Food chains were starting to collapse and most ecosystems were suffering. The massive asteroid that struck the Earth at this time was the final blow for many species. They could not adapt to the changing conditions, the destruction of their habitats and the disappearance of their food sources, and thus became extinct.
5. Well there were no sea dinosours, those things weren't technicaly dinosaurs. But if you know about the theory of the big rock hitting earth... the plankton in the oceans, which are photosynthetic, would have hav some trouble and because the ecosystem is built around them it would have effected those reptiles. Not all animals died because of the rock hitting, turtles and celocanths live to this day, defying the odds, and I don't know why. Keep in mind that a theory can be disproved. I have heard anothe hypothosis proposed that said that rodents killed the dinos cuz they spread disease. Who knows