Sea Otter Facts
for Kids

Sea otters are a keystone species because they control sea urchin populations. Without otters, urchins overgraze kelp forests until they collapse into barren rock, wiping out habitat for countless fish, invertebrates, and other species. By eating urchins, otters help kelp forests thrive, which in turn supports biodiversity and stores significant amounts of carbon.

Sea otters rely on the densest fur of any animal — up to a million hairs per square inch — instead of blubber for insulation. This fur traps a layer of air against their skin, but it requires constant grooming and enormous amounts of food (up to 25% of their body weight daily) to fuel the metabolism needed to stay warm.

Global sea otter populations have recovered to roughly 100,000 individuals, up from as few as 1,000–2,000 survivors after the fur trade nearly wiped them out by the early 1900s. Despite this recovery, they remain classified as Endangered due to oil spill risk, disease, and localized population declines, particularly in parts of Alaska and California.

Yes — sea otters are among the small number of non-primate animals documented using tools in the wild. They select and carry favorite rocks to crack open hard-shelled prey like clams, mussels, and sea urchins, often storing a preferred rock in a skin pouch under their foreleg between uses.

Sea otters often rest in groups called rafts and hold hands, or wrap themselves in kelp, to keep from drifting apart on ocean currents while they sleep. This behavior helps keep the group together and protects vulnerable pups from floating away from their mothers.