The coelacanth is a type of bottom-dwelling fish that is primarily found in the Indian Ocean near the African coast. They are often called "living fossils" because they have existed for approximately 360 million years.
Coelacanths were once thought to have gone extinct about 65 million years ago, near the end of the Cretaceous period. The species was rediscovered by accident in 1938, when a living specimen was caught by fishermen. Several other living coelacanths have been caught since that time, although the fish remains rare. It is currently considered an endangered species.
A second species of coelacanth lives near Indonesia. Both species are notable for their four fleshy fins, which look somewhat like legs. Coelacanths also have a unique hinged jaw, which lets them eat large prey. Their scales are rough and knitted together to form an armor-like protective layer.
They are typically found at a depth of about 500 to 800 feet. This is known as the twilight zone because the light is very faint light. Their diet is largely made up of cephalopods, such as cuttlefish and octopus, but they are opportunistic feeders.
Coelacanths may provide valuable information about how the first land animals evolved. Some scientists think their lobe-like fins are similar to those of the fish that developed into tetrapods. The motion of the fins while the fish swims is similar to the way tetrapods move their legs.