In the “Crab Lab,” the limits of feisty green crabs from Maine are put to the test.

Markus Frederich and his students at the University of New England in Maine placed about a dozen crabs in a bucket, pumped in nitrogen to deprive them of oxygen for 45 minutes and then put them on an underwater treadmill.

Some crabs ran for as long as five minutes and still survived.

“That is pretty wild,” Professor Frederich said. “Students were in awe.”

In the mid-1800s, European green crabs hitched a ride on boats and came to the United States. But over the past few years, a genetically different European green crab