In fact, otter and otter refer to the same animal, and the correct spelling should be otter.

Otter (scientific name: Lutralutra), also known as otter, otter cat and water dog, is a semi-aquatic medium-sized carnivore. The otter is 70 ~ 75cm long, 30 ~ 55cm long and weighs 5 ~14kg. The otter is slender and streamlined. The head is slightly flat, the limbs are thick and short, the claws are large and obvious, and the tail is long and flat. Body hair is long and thin, brown and black or brown. Otters inhabit rivers, streams, lakes and swamps, with dense forests and coasts.