Huge ancient sea scorpions, long characterized as terrors of the sea, may actually have been timid scavengers or even vegetarians, U.S. scientists say.
Sea scorpions, known as pterygotid eurypterids, were arthropods, like insects and crabs. Though not actually scorpions, many of the animals had tails ending in spikes, which got them their name.
These 8-foot-long monstrous bugs were believed to be terrors of ancient oceans 470 million to 370 million years ago, long before the dinosaurs appeared, with large claws laden with sharp spines.
But researchers say those claws possessed very little crushing power.
Analyzing fossil claws from a group of one of the largest sea scorpions, Acutiramus, Richard Laub, a paleontologist at the Buffalo Museum of Science, calculated that the pincers could apply no more than 5 newtons of force without damaging themselves.
This would make them incapable of cracking into even a medium-size horseshoe crab's armor, which needs 8 to 17 newtons to break open.
"We have a group that in many cases was perceived as big, bad animals, sort of the Tyrannosaurus rex of the seas of their time," Laub says.
"Our results derail the image of these imposing-looking animals, the largest arthropods yet known to have existed, as fearsome predators," Laub said. "It opens the possibility that they were scavengers or even vegetarians."