* Warm-blooded: Like all mammals, sea otters maintain a constant internal body temperature, regardless of the surrounding water temperature.
* Breathe air: Sea otters have lungs and need to surface regularly to breathe.
* Give birth to live young: Sea otters do not lay eggs, they give birth to live pups.
* Nurse their young: Female sea otters produce milk to nourish their pups.
* Have hair: Sea otters have a thick fur coat that helps them stay warm in the cold water.
* Are warm-blooded: They maintain a constant internal body temperature, unlike fish or reptiles.
While they live in the ocean and have adapted to a marine lifestyle, they still share the fundamental traits that define mammals.