The beaver world doesn't consist of seemingly endless species from all corners of the planet, but rather just two surviving ones. These two species are the Eurasian beaver (Castor fiber) and the North American beaver (Castor canadensis). Although their reproductive patterns differ from the other slightly, they are still close in many ways -- think breeding intervals, for example.
North American Beaver Mating
Both genders attain reproductive maturity when they're around 3 years old. Unlike many other types of animals, North American beavers practice monogamy. Pairs reproduce together as long as they are both breathing. However, in cases of death, they do look for new partners. The breeding season commences in January and February. Female North American beavers are usually pregnant for around 107 days in total, according to the Natural Science Research Laboratory of Texas Tech University.
North American Beaver Offspring
North American beaver mothers typically give birth to their little ones either during the late spring or the beginning of the summer each year. Although most beavers only reproduce once a year, there are some exceptions. Occasionally, females welcome offspring again towards the end of the summer or the start of the fall. On average, North American beaver litters are made up of three or four little ones. Baby beavers -- or "kits" -- are born well-developed, with open eyes and ample body fur. They are comfortable with the water in the span of a single day post-birth, and are even able to swim by that point. Weaning occurs at approximately 2 weeks in age, although the male and female beavers, as a parental team, rear the kits together for a maximum of 2 years.
Eurasian Beaver Mating
Eurasian beavers are also monogamous creatures, just like their buddies across the pond. These beavers, too, choose one permanent partner and stick together. Also like North American beavers, Eurasian beavers begin breeding each year in January or February. However, unseasonably high temperatures can sometimes lead to an advanced start -- sometimes as early as December. The mothers usually are pregnant with their babies for anywhere between 60 and 128 days. Late spring or early summer births are the norm for these beavers, as well.
Eurasian Beaver Offspring
For the most part, Eurasian beaver litters include between one and three youngsters. However, some litters in rare cases can actually exceed six kits. Unlike North American beavers, the females do the bulk of the child rearing, although they do receive a lot of assistance from other mature members of their social unit, particularly in the feeding department. Weaning generally finishes once the kits are 6 weeks in age, although as with North American beavers, the offspring tend to stay close to mom until their second year -- or at least close to it.
- World Association of Zoos and Aquariums: Eurasian Beaver
- Animal Diversity Web: Castor Canadensis
- Animal Diversity Web: Castor Fiber
- The IUCN Red List of Threatened Species: Castor Fiber
- Smithsonite National Museum of Natural History: Castor Canadensis
- NatureWorks: Beaver - Castor Canadensis
- Natural Science Research Laboratory: Castor Canadensis