The capelin or caplin (Mallotus villosus) is a small forage fish of the smelt family found in the North Atlantic, North Pacific, and Arctic oceans. In summer, it grazes on dense swarms of plankton at the edge of the ice shelf. Larger capelin also eat a great deal of krill and other crustaceans. Among others, whales, seals, Atlantic cod, Atlantic mackerel, squid, and seabirds prey on capelin, in particular during the spawning season of the capelin while it migrates southwards. Capelin spawn on sand and gravel bottoms or sandy beaches at the age of 2–6 years, and have an extremely high mortality rate on the beaches after spawning, for males close to 100%. Males reach 20 cm (8 in) in length, while females are up to 25.2 cm (10 in) long. They are olive-colored dorsally, shading to silver on sides. Males have a translucent ridge on both sides of their bodies. The ventral aspects of the males iridesce reddish at the time of spawn.