The Doyarchu is described as an animal that is about the size of a crocodile or a big dog, but resembles a cross between a dog and an otter. It either has sleek black fur that fits very snugly to the body, or it has smooth, slimy black skin with no fur at all. The hindquarters are bigger than the forequarters and resemble a dog, especially a powerfully-built greyhound. The paws are big in proportion to the rest of the body, the same as most aquatic mammals. The head is sleek, the neck is long, and the tail is long and slender. A few individuals are described as having one or more patches of white, especially a large patch in the middle of the chest. It goes by various monikers, ex. dobhar-chu, anchu, water dog and Irish crocodile.