Scientists concluded that some fossilized foot marks left by a big meat-eater on a lake bed in northern Spain 125 million years ago provide strong evidence that at least some dinosaurs were good swimmers.
Dinosaurs ruled the land from about 230 million years ago to 65 million years ago. But how they did in the water has been less clear.
There were numerous huge, fully marine reptiles living at the same time, but they were not dinosaurs and in fact were only very distantly related to them.
Scientists have been seeking evidence that dinosaurs — like today’s large mammals such as elephants and tigers — were capable of swimming when circumstances demanded, like hunting in wet ecosystems, crossing rivers or escaping floods.
Previously discovered fossils showed swimming tracks apparently left by other dinosaurs such as sauropods — long-necked animals like Diplodocus — and duckbilled dinosaurs.
The new tracks provided the first definitive evidence of an active swimming behavior in dinosaurs and are the best record of swimming by theropods, researchers said.