An otter is a carnivorous mammal that belongs to the subfamily Lutrinae. There are 13 extant species of otters, all of which are semiaquatic, aquatic, or marine, with diets based on fish and invertebrates. Otters have long, sleek bodies with dense, glossy brown fur from head to toe, and they vary in size, ranging from 38 to 44 inches in length and weighing from 10 to 75 pounds. They have short legs, webbed toes, and tapered, muscular tails that aid in swimming, and they can stay underwater for up to eight minutes because of their closeable nostrils and ears. Otters are smart and playful animals, and they are known to engage in various behaviors for sheer enjoyment, such as making waterslides and sliding on them into the water. Otters are also one of the few mammals that use tools, with the sea otters tool of choice being a rock that can be used as a hammer or anvil to break open hard-shelled prey. In the LGBT community, otter is a term used to describe a type of gay man who generally has a lot of body hair, much like bears, but is smaller in frame and/or weighs considerably less than bears.