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Native Rodents of Orange County: Part 4

Updated: Mar 18, 2022

To conclude our native rodents spotlight series, we will discuss the North American beaver, Castor canadensis subauratus, also known as Golden beaver. The only known beaver population in Orange County is along the San Mateo creek at the border of Orange County and San Diego County. It is the largest rodent in North America. The beaver is rich brown and has a wide paddle-shaped tail. Adults usually weigh between 24 to 71 pounds, with 44 pounds being the typical mass. The head-and-body length is 29–35 inches, with the tail adding a further 7.9–14 inches. The beaver is semi-aquatic. It has a large flat paddle-shaped tail and large webbed hind feet. The tail is about 10 inches long and 6 inches wide. The tail, because of its thickness, can cause a loud splash when it slaps the water. The beaver is also recognized by huge front teeth.

Beaver gathering resources to build their dam. Photo by Cheryl Reynolds | Worth A Dam

Beavers are good swimmers and select rivers, streams, ponds, and lakes to build their dams and lodges. A few natural signs tell you a beaver is near. A stick-and-mud dam built across a stream at the edge of a lake and stumps of small trees in the area showing tooth marks will let you know a beaver is nearby. They live in family groups called colonies. They have a lifespan of 10-15 years in the wild and can live 20 years in captivity.

These beavers are herbivores that like to eat a few different kinds of trees, including aspen, poplar, birch, maple, willow, and alder. Beavers also eat bark and small twigs and store small sections of logs underwater near their lodge to eat later. Natural predators of beavers include coyotes, wolves, and mountain lions.

Beaver pairs are monogamous, staying together for multiple breeding seasons. They breed between late December to May.

Ecologically, the beaver is a keystone species, increasing biodiversity in its territory by creating ponds and wetlands. As wetlands are formed and riparian habitats are enlarged, aquatic plants colonize newly available watery habitats. Insect, invertebrates, fish, mammals, and bird diversities are also expanded.

North American beaver mother with its baby. Photo by Suzi Eszterhas

Although there are many native rodents that can be found in Orange County (OC), we have discussed only four of them in this series. There are many other native rodent species that live in OC depending on their nature and habitat preference. However, due to the challenges and threats to their natural habitats, the native rodent population is at risk. Human encroachment, construction, water diversion and damming, invasive rodent species, and wildfires have immensely affected the natural habitats of rodents. As rodents not only balance the natural ecosystem but also support agriculture to a great extent, so we all need to protect them. You have already taken initiative by knowing about our little neighbors by visiting the OC Habitats website and blog and learning about native rodents of OC. To get involved in habitat conservation for these species and more, you can volunteer at a variety of local nonprofits such as OC Habitats, OC Coast Keeper, Surfrider Foundation, Crystal Cove Conservancy, Laguna Ocean Foundation, and more. You can support your local environment by contacting your local, regional, state, and federal government officials about ensuring protection for native rodents and their habitats.

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