Which of the following is an aquatic mammal that uses tools?
Considering octopus, crow, sea otter and elephant, the answer is: sea otter.
Sea otters have loose pouches of skin under their armpits to store a rock, which they use as an anvil or hammer for breaking open hard-shelled prey and the food they’ve foraged. Sea otters eat 25% of their body weight in food every day.
Sea otters love to feast on shelled creatures such as clams, mussels and crabs— all snacks that are difficult to get into. In order to get to the good stuff on the inside, sea otters have designed a unique method of cracking and hitting their meal with tools.
One way that the sea otter secures dinner is by first diving under the water to secure a rock. With that rock, the otter will roll onto their back, creating a hard surface on which to crack the hard-shelled meal. The otter will hold the shell in both hands and drive it down onto the rock until the mussel, clam or other creature cracks open. Oftentimes, otter pups will observe their mother using the tool before they are able to complete the act themselves. For this reason, there is an uneven use of tools across regional otter communities.
Sea otters have other impressive qualities, however. For one, their fur is incredibly thick and water resistant, with up to a million hairs per square inch. Unlike other marine animals, sea otters do not possess a layer of blubber to keep them warm, so this thick fur is essential to survival.
Learn more about sea otters here.