 The ratfish lays leathery egg cases on the bottom of muddy or sandy areas, which are often mistaken by divers as something inanimate.While mainly a deep-water species, it occurs at shallower depths in the northern part of its range.The generic name, "Hydrolagus", comes from the Greek words ὕδωρ, meaning water, and λαγώς/λαγῶς, meaning hare, and the specific name honors Alexander Collie, who was a ship surgeon and early naturalist.