California's sea otters have struggled for years to get off the endangered species list. Obstacles include diseases, parasites-- even the occasional collision with a boat.
Now, they are facing their biggest challenge yet, the great white shark bite. According to the Mercury News, for reasons still a mystery to scientists, the number of sea otters killed by sharks has soared in recent years, and great whites are the main suspects.
In the mid-1990s, about 10 percent of the dead sea otters found along the coast had shark bites.
Today, it's roughly 30 percent - and growing.
Shark attacks now represent the largest hurdle to the otters' recovery from the endangered species list.
Last year, 70 sea otters bearing evidence of shark attacks washed ashore between San Mateo County and Santa Barbara.
One theory for the great white's changing hunting habits, is the possibility that the sharks are mistaking otters for marine mammals that they regularly eat, such as sea lions and elephant seals, whose populations have grown in recent years.