This video from the USA says about itself:
26 May 2016
An abalone can be pretty hard to pry off a rock. Just ask a sea otter! But if there’s a handy stone nearby? Good luck abalone!
An otter fuels its fast metabolism by eating up to a quarter of its weight in food a day. (A 150-pound person would have to eat 35 to 40 pounds of food a day to match that!)
A sea otter may hunt on the seafloor, but always returns to the surface to eat. Floating there on its back, it uses its chest as a table. (And if dinner’s a crab or clam, the otter may use a rock to crack open its prey.)
An otter’s coat has pockets—pouches of loose skin under each forearm. An otter uses them to stash prey during a dive, which leaves its paws free to hunt some more.
From Science News:
Tool use in sea otters doesn’t run in the family
by Helen Thompson
8:44pm, March 21, 2017
Aside from being adorable, sea otters and Indo-Pacific bottlenose dolphins share an ecological feat: Both species use tools. Otters crack open snails with rocks, and dolphins carry cone-shaped sponges to protect their snouts while scavenging for rock dwelling fish.
Researchers have linked tool use in dolphins to a set of differences in mitochondrial DNA — which passes from mother to offspring — suggesting that tool-use behavior may be inherited. Biologist Katherine Ralls of the Smithsonian Institution in Washington, D.C., and her colleagues looked for a similar pattern in otters off the California coast. The team tracked diet (primarily abalone, crab, mussels, clams, urchins or snails) and tool use in the wild and analyzed DNA from 197 individual otters.
Otters that ate lots of hard-shelled snails — and used tools most frequently — rarely shared a common pattern in mitochondrial DNA, nor were they more closely related to other tool-users than any other otter in the population.
Unlike dolphins, sea otters may all be predisposed to using tools because their ancestors probably lived off mollusks, which required cracking open. However, modern otters only take up tools when their diet requires them, the researchers report March 21 in Biology Letters.
University of Wyoming researchers have been studying how best to bolster the southern sea otter population, which suffers from low genetic diversity and has been further ravaged by Toxoplasma brain disease and others, shark attacks and illegal shootings by fishermen. Currently hovering at around 3,000 animals along the California coast, this small subspecies is listed as a threatened species under the federal Endangered Species Act: here.