Mountain Beaver Aplodontia rufa

A rodent from Pacific North America, from British Columbia to California. They are not related to true beavers. Originating in the late Oligocene, the mountain beaver has retained a number of primitive characteristics that make it a living fossil, such as their chewing mechanism and kidney function.

Contrary to their name, Mountain Beavers (Aplodontia rufa) do not build dams, nor do they have flat paddle-shaped tails. 

In fact, they’re not even beavers! Aplodontia is considered to be the most primitive living rodent, and it looks something like an oversized gopher. 

Point Reyes National Seashore, in northern California, hosts a subspecies of mountain beaver found nowhere else. Spotting one can be tricky because they spend most of their time in underground burrows, leaving only to forage for plants. 

Starting this year, a collaborative project between the National Park Service and University of California Berkeley launched a survey to better understand and track this subspecies. Surveyors are searching for mountain beaver burrows across the Point Reyes peninsula. The burrow locations collected over the two-year survey will help train a model and create a map predicting where these animals are likely to live. 

Ultimately, this research will help guide management practices, particularly related wildfire preparedness, to protect this unique species.

To learn more visit: https://go.nps.gov/mountainbeavermonitoring

Mountain Beaver (Aplodontia rufa)

- NW United States and Western Canada

The term "beaver" often leads people to imagine a large rodent living in ponds and building dams. This is not the case with the mountain beaver (Aplodontia rufa). Mountain beavers are not actually a kind of beaver though, and are an unusual and primitive species of rodent.

They are about the size of a muskrat, 10–12 inches (27–30 cm) long. However, they have a very short tail, less than one-half inch (1 cm) long. Mountain beavers live in underground burrows typically dug in dense thickets or in forest openings. The burrows have separate chambers for excrement, food storage and nesting. The presence of burrow openings is often the most obvious evidence of mountain beaver activity. Typically, there are multiple openings...

Mountain beavers are seldom seen because they feed mostly at night. They eat a wide variety of vegetation including coyote brush, sword fern, cow parsnip, blackberries, poison oak, California nettle, foxglove, and thistle. A mountain beaver needs 1/3 of its body weight in water every day because its kidneys are simple and inefficient at conserving water. This means an adult needs to consume 1–2 cups (295–450 ml) of water daily, by drinking or from food. Because of this, mountain beavers are restricted to areas near water or with extensive summer fog along the Pacific coast...

Read more: https://www.nps.gov/pore/learn/nature/mountain_beaver.htm

The Mountain Beaver That Is Not A Beaver | Cool Green Science

“The mountain beaver is a rodent like no other. Just don’t call it a living fossil.” If you read Prince Dobalob Builds a Zeppelin, you have already been introduced to a Mountain Beaver. In the story, the butler, Kipling, is a Mountain Beaver. The book features many rodents, but Aplodontia rufa is arguably the most obscure of them. I run into lots of people who are unfamiliar with capybaras…

[Photo source]

Okay probably not so lemme tell you some fun facts about them:

They only live on the west coast of North America. BC, WA, OR and CA.

They are the only member of their family and genus. 

They aren’t related to beavers. 

They live in these giant ass tunnel systems and I know multiple people who have broken their ankle/leg by stepping in a mountain beaver hole. 

Also I teach kids in the forest all summer and one jumped off a log and went up to his waist in an aplodontia burrow. There was a good 5 seconds where I was like “yeah that kid just jumped into a portal he’s a goner”. 

They are basically blind and are known to repeatedly walk into people’s feet.

They love to collect ferns, but naturalists don’t know what they do with them (they don’t appear to eat them or use them for bedding).

Also sometimes they’ll collect ferns from their tunnels so you’ll just see these ferns wiggling and then disappear into the ground.

ALSO they sometimes forget about their ferns so they’ll just leave them lying around the forest. 

They like to chew sticks (like a beaver) but not the ground level ones. They climb 2-3 feet up into trees to get the primo ones (I guess?)  

Are furry blobs. 

They’re like the honey badgers of our area (they don’t give a fuck) but also a staple food source for predators (because they don’t give a fuck). 

There’s a lot of misinformation because people assume stuff about them without thoroughly researching it! Multiple of my peers are focusing on studying aplodontia habits and patterns.