Otters are the most aquatic members of the weasel family. With the exception of the aptly named sea otter, which lives (and sleeps, mates, gives birth, and rears its young) only in the ocean, otters inhabit all types of fresh waters, as well as estuaries and marine coves. They can be found on every continent except Antarctica, and all thirteen species are listed as threatened or endangered.

Dense fur, webbed feet, and specially designed corneas are only a few of the North American river otter's ingenious adaptations to its aquatic environment. This engaging mammal originally ranged from arctic Alaska to southern Florida and Texas. But by the beginning of the twentieth century it was extirpated (completely eliminated) in many states, due to excessive trapping, habitat destruction, and water pollution.

In 1995 the New York River Otter Project was formed to bring the river otter back to central and western New York State, where water quality had improved enough to sustain a sizable population. It costs about $1000 per otter, but over 150 have been reintroduced so far, in nine locations. The goal is to release between 30 and 120 more, in the hopes that they will settle in, reproduce, and thrive.