Lamprey
Jawless fish with a sucking mouth, found in temperate waters.
Lampreys are a group of jawless fish comprising the order Petromyzontiformes, the sole order in the class Petromyzontida. They are characterized by a toothed, funnel-like sucking mouth and superficially resemble eels, though they lack paired fins. About 38 extant species are known, classified into three families: two small families in the Southern Hemisphere (Geotriidae, Mordaciidae) and one large family in the Northern Hemisphere (Petromyzontidae). Genetic evidence suggests lampreys are more closely related to hagfish than to jawed vertebrates, forming the superclass Cyclostomi.
- Scientific classification
- Order Petromyzontiformes, class Petromyzontida
- Number of extant species
- About 38
- Number of extinct species
- Around seven known
- Largest species
- Sea lamprey, maximum body length around 1.2 m (3.9 ft)
- Feeding types
- 18 carnivorous species; noncarnivorous species do not feed as adults
Lore & Background
Lampreys spend most of their lives in the juvenile 'ammocoete' stage, burrowing into sediment and filter-feeding. Adult carnivorous lampreys feed by boring into the flesh of other fish or, rarely, marine mammals to consume flesh or blood; only 18 species engage in this predatory lifestyle, with Caspiomyzon suggested to feed on carrion. All noncarnivorous forms are freshwater species, and their adults do not feed, living on reserves acquired as ammocoetes. Lampreys are among the most energy-efficient swimmers, generating low-pressure zones that pull their bodies through water.
Reader's Guide
Lampreys are significant as one of the only two living groups of jawless fish, the other being hagfish, and their genetic relationship helps clarify early vertebrate evolution. Their unique anatomy—including a cartilaginous skeleton, a toothed sucking mouth, and multiple eye types—provides insight into the transition from jawless to jawed vertebrates. Ecologically, lampreys play varied roles: some are parasitic on fish, while noncarnivorous species do not feed as adults. Their distribution is affected by habitat loss, overfishing, pollution, and dams, but artificial channels have also created new habitats, as seen with sea lampreys becoming an introduced pest in the Great Lakes. Lampreys are valued as food in some regions, and their climbing ability is studied to design ramps aiding reproduction. The reduction of pollution in the Thames and River Wear has led to recent sightings in London and Chester-le-Street.
Did You Know?
- The common name 'lamprey' may derive from Latin lampetra, meaning 'stone licker' (lambere 'to lick' + petra 'stone'), though the etymology is uncertain.
- Lampreys have been described as the only living vertebrates to have four eyes: a pair of regular eyes and two parietal eyes (pineal and parapineal), except members of Mordacia.
- Lamprey teeth are made of keratin and other proteins, with a hollow core to allow replacement teeth to grow underneath.
- The last common ancestor of lampreys appears to have been specialized to feed on the blood and body fluids of other fish after metamorphosis.
Frequently Asked Questions
What are lampreys?
Lampreys are jawless, eel-like fish that use a circular, toothed mouth to attach to and feed on other animals. They belong to their own class (Petromyzontida) and are found in temperate waters around the world.
How many species of lamprey are there?
Scientists have identified roughly 38 living species, split across three families. A couple of small families live in Southern Hemisphere waters, while the bulk of species fall into one large Northern Hemisphere family.
What is the largest lamprey?
The sea lamprey holds that title, reaching up to about 1.2 meters (roughly 3.9 feet) in length. It is the most well-known member of the group.
How do lampreys get their food?
About 18 species are carnivorous, using their suction-cup mouth to latch onto a host and feed on its fluids. The remaining species stop eating entirely once they reach adulthood.
Are lampreys more closely related to hagfish or to jawed fish?
Despite looking like distant cousins of sharks and bony fish, genetic evidence places lampreys closer to hagfish. Together they form the superclass Cyclostomi, the jawless vertebrates.
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