Study shows sea otters' hunger helps fix California wetlands.

Sea otters have returned to a part of California, and their love for eating striped shore crabs is helping to protect the marshland there. These crabs can damage the marsh by eating the roots of grass and making the soil weak, but with otters eating the crabs, the damage is reduced.

Researchers discovered that when sea otters eat crabs in a tidal area near Monterey, California, it helps stop the land from eroding too quickly. They found that even though otters don't stop erosion completely, they slow it down to a natural pace.

Sea otters used to live all over from Alaska to California and even into Russia and Japan, but they were almost wiped out because of hunting for their fur. Thanks to laws stopping the hunting and efforts to restore their homes, sea otters have started to come back.

Scientists looking into how otters coming back affected the area found out that places without otters had much more erosion. Similar research has shown that other big predators, like wolves in Yellowstone, also help their environments by keeping other animal populations in check.

This study not only watches what happens but sets up experiments to clearly show the good things otters do for their environment, like helping plants under the water by eating sea urchins. Experts think otters are really good at finding and eating things that can harm the places where they live.