Lamprey (Lampetra) on rainbow trout.—Oxford Scientific Films/Bruce Coleman Ltd.

Any of about 22 species of primitive, jawless fishes (with hagfishes in class Agnatha). Lampreys live in coastal and freshwater in temperate regions worldwide except Africa. Eel-like, scaleless animals, they are 6–40 in. (15–100 cm) long. Lampreys have well-developed eyes, a single nostril on top of the head, a cartilaginous skeleton, and a sucking mouth with horny teeth surrounding the round opening. They spend years as burrowing larvae; adults of most species move into the sea. They attach to fish with their mouth and feed on their host's blood and tissues. Some species will remain in freshwater, notably the sea lamprey, which entered the Great Lakes and nearly eliminated lake trout and other commercially important fishes there.

This entry comes from Encyclopædia Britannica Concise.
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