A southern sea otter swims on her back. Her pup rides on her belly. The mother carefully wraps a seaweed leaf around the baby otter. This will keep the pup from floating away while she dives underwater to hunt. When she returns, she holds a spiky-shelled creature called a sea urchin. She shares the meat from inside the shell with the pup. 

Today, this is a common scene along the California coast. But that wasn’t always the case. Sea otters were once nearly wiped out. 

Over the past century, the critters have started to bounce back. That’s a good thing—and not only for sea otters. A recent study shows that these creatures are helping to protect kelp forests, the ecosystems they call home.  

A southern sea otter swims on her back. Her pup rides on her belly. The mother carefully wraps a seaweed leaf around the baby otter. This will keep the pup from floating away. Meanwhile she dives underwater to hunt. When she returns, she holds a spiky-shelled creature. It’s called a sea urchin. She shares the meat from inside the shell with the pup. 

Today, this is a common scene along the California coast. But that wasn’t always the case. Sea otters were once nearly wiped out. 

Over the past century, the critters have started to bounce back. That’s a good thing. And it’s good not only for sea otters. A recent study shows that these creatures are helping to protect kelp forests. These are the ecosystems they call home.  

Sea otters are a keystone species. That means they play a big role in their ecosystems (see “Kelp Helpers”). 

But sadly, humans nearly drove otters to extinction. At one time, there were as many as 20,000 southern sea otters in California. In the 1700s, people began hunting them for their thick fur. By 1911, only about 50 otters remained. That year, laws were passed that made it illegal to hunt them. Since then, their population has been slowly growing. 

Sea otters are a keystone species. That means they play a big role in their ecosystems (see “Kelp Helpers”). 

But sadly, humans nearly drove otters to extinction. At one time, there were as many as 20,000 southern sea otters in California. In the 1700s, people began hunting them. They were hunted for their thick fur. By 1911, only about 50 otters remained. That year, laws were passed that made it illegal to hunt them. Since then, their population has been slowly growing. 

Today, there are about 3,000 sea otters. Even that small number has had a huge effect, explains Jess Fujii. She works at the Monterey Bay Aquarium in California. Researchers there released a study in January that shows how otters are helping kelp forests.

“In areas where sea otters returned, we saw kelp growth compared to a hundred years ago,” Fujii says. “In areas where otters have not returned, we saw losses in kelp.”

Just one otter can eat hundreds of sea urchins a day. So, otters can prevent urchins from destroying entire forests. 

“Otters are just trying to find food and survive,” Fujii explains. “But in doing so, they’re helping kelp forests provide homes and food for hundreds of other species.”

Today, there are about 3,000 sea otters. Even that small number has had a huge effect, explains Jess Fujii. She works at the Monterey Bay Aquarium in California. Researchers there released a study in January. The study shows how otters are helping kelp forests.

“In areas where sea otters returned, we saw kelp growth compared to a hundred years ago,” Fujii says. “In areas where otters have not returned, we saw losses in kelp.”

Just one otter can eat hundreds of sea urchins a day. So otters can prevent urchins from destroying entire forests. 

“Otters are just trying to find food and survive,” Fujii explains. “But in doing so, they’re helping kelp forests provide homes and food for hundreds of other species.”