Vulpes vulpes (Red Fox)
European Beaver (Castor finer)
Arvicola amphibius (Water Vole)
Microtus agrestis (Field Vole)
Erinaceus europaeus (Hedgehog)
Lepus europaeus (Brown Hare)
Lutra lutra (Otter)
Martes martes (Pine Marten)
Meles meles (Badger)
Mustela erminea (Stoat)
Sciurus vulgaris (Red Squirrel)
Sorex araneus (Common Shrew)
Talpa europaea (European Mole)
The European (Eurasian) beaver (Castor fiber) is a large, semi-aquatic, herbivorous rodent and ecosystem engineer, weighing 12-38 kg, known for creating dams and lodges to live in family groups. They are monogamous, with 1-4 kits born in spring, staying with parents for two years. These keystone species are highly adapted for aquatic life with waterproof fur, webbed feet, and flattened tails, and are crucial for improving biodiversity and water quality.
Biology and Adaptations
Physical Features: The European beaver has a 75-90 cm body, plus a 28-38 cm flattened tail, acting as a rudder for swimming. Their teeth are orange due to iron-reinforced enamel, and they grow continuously.
Aquatic Specialization: They can hold their breath for up to 15 minutes, using a third, clear eyelid (nictitating membrane) to see underwater. Their fur is thick and waterproof.
Diet: Exclusively vegetarian, feeding on aquatic vegetation, bark, and woody stems.
Distinction: The European beaver is genetically distinct from the North American species (Castor canadensis), with 48 chromosomes compared to 40, making them incompatible for interbreeding.
Family Life and Structure
Group Size: They live in family groups, typically consisting of an adult pair and their kits (1-4) and sub-adults (up to 12 total individuals, usually 6 or fewer).
Reproduction: Breeding occurs annually in early spring (January-February), with a gestation period of 60-128 days.
Dispersal: Young remain with their parents for two years, helping with the family lodge, before dispersing to form their own territories.
Ecosystem Engineering
Habitat Modification: Beavers cut down trees and build dams with wood and mud to create deep-water, safe habitats (lodges).
Environmental Impact: Their activities create, maintain, and restore wetlands, which filters water, traps sediment, helps control flooding, and supports numerous other species.
Conservation Status
Once near extinction by the 16th century, they have been successfully reintroduced to parts of Europe and the UK. As of 2020, the population is estimated at over one million.