Sea Lamprey Clings to a Fish

The sea lamprey, a vertebrate parasite, belongs to the most primitive group of living fish, the agnathans, or jawless fish. In this species the lower jaw is missing and the upper jaw is modified into a sucking disk. The lamprey feeds on blood by using this disk to attach to another fish and drilling a small hole into the fish’s side with its small, muscular tongue. The parasitic action rarely kills the host, but wounds caused by lampreys often become infected.

Berthoule/Photo Researchers, Inc.

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Vertebrate; Lamprey; Ecology

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