Lampreys · Petromyzontiformes · Petromyzontidae

River Lamprey

Lampetra fluviatilis

Least Concern

The species is abundant and widely distributed; it faces no significant short-term risk. See full glossary

It is one of the most primitive living vertebrates, entirely without true jaws and with a wholly cartilaginous skeleton. At spawning, both parents die shortly after the eggs are laid.

Weight

50 g – 150 g

Size

32 cm – 50 cm

Lifespan

6 years

Diet

Carnivore

Feeds mainly on other animals.

Activity

Nocturnal

Active mainly at night.

Social structure

Solitary

Lives and hunts alone, joining others only to breed.

Sighting difficulty

Easy

FreshwaterCarnivore Nocturnal Solitary Freshwater

18countries 28parks 16dive sites1same family

Fun facts

It has no true jaws at all, making it one of the most primitive living vertebrates.
The male coils around the female with his sucker mouth during spawning.
Its blind larvae (ammocoetes) live buried in the sediment for years.

Life cycle & biology

Skeleton type: Vertebrate - jawless cartilaginous skeleton (agnathan)
Habitat & environment: Fresh-water rivers, streams and lakes of Europe, with a coastal marine phase in its migratory (anadromous) form
Birth weight: A tiny egg; a blind ammocoete larva on hatching
Size at birth: A tiny blind ammocoete larva that lives buried in the sediment for several years
Sexual maturity: Reached after metamorphosis at 13 cm long, generally between 3 and 5 years old
Gestation / incubation: The egg develops over a few weeks (no precise figure found)
Litter / clutch size: Up to 25,000 eggs per female

Sources consulted: FishBase; The Wildlife Trusts; Leicestershire and Rutland Wildlife Trust; Forth Rivers Trust; AnAge (genomics.senescence.info); Devon Wildlife Trust