Jorgensen quoted in National Geographic on shark attacks on sea otters
Great white sharks eat fish when they are young, but after the first few years they grow new teeth and start eating marine mammals, notably fatty seals and sea lions. The sharks need the rich calories from the mammals' blubber to keep their bodies warm.
Sea otters are mostly muscle, skin, bones, and luxurious fur.
"They have more strands of hair per square inch than any other mammal, which they use to trap air," says Salvador Jorgensen, a white shark expert with the Monterey Bay Aquarium. “That’s how they insulate.”
For a white shark, that's not much of a meal, which may explain why otters don't get eaten, Jorgensen says. But it’s clear white sharks are the culprit. The bite marks match white shark jaws, and wildlife pathologists often find broken white shark teeth in the mammals.