Mammals · Rodentia · Castoridae

Eurasian Beaver

Castor fiber

Least Concern

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

It is monogamous, forming stable pairs that breed together year after year — unusual among rodents. Its dams and lodges transform river ecosystems profoundly.

Weight

12.5 kg – 38 kg

Size

74 cm – 90 cm

Lifespan

9 years

Diet

Herbivore

Feeds mainly on plants.

Activity

Nocturnal

Active mainly at night.

Social structure

In pairs

Usually lives in pairs, sometimes for life.

Sighting difficulty

Easy

FreshwaterHerbivore Nocturnal In pairs Freshwater Mammal

32countries 20parks1same family

Fun facts

It is monogamous, forming stable pairs that breed together year after year.
Its dams and lodges transform river ecosystems profoundly.
It was all but extinct in the nineteenth and twentieth centuries, with only some 1,200 animals left.
conservaciónIt has been successfully reintroduced across many European countries after being hunted almost to extinction for its fur and for a glandular secretion once used in perfumery and medicine.

Life cycle & biology

Skeleton type: Vertebrate - internal bony skeleton with continuously growing incisors (mammal)
Habitat & environment: Freshwater rivers, lakes and wetlands of Europe and Asia, in wooded country
Birth weight: 230 - 630 grams (average ~530 g)
Size at birth: Precocial: able to swim within hours of birth
Sexual maturity: 2-3 years
Gestation / incubation: 60-128 days (usual reference ~105-107 days)
Litter / clutch size: 1 to 6 young per litter (most commonly 2-3)
Lifespan in captivity: Documented record of 13.7 years in captivity

Sources consulted: A-Z Animals; Animal Diversity Web; AnAge (genomics.senescence.info); Wildlife Online; Mammal Society; PMC (fetal development study); PMC (haematology study)