Mountain Beaver
(Aplodontia rufa) Journal (latest update 9/16/07)
Researchers and biologists have long been aware of this most unusual and interesting species, first reported by Lewis and Clark. Like most people however, few have actually seen the species in the wild. I have been interested in this species for many years. To learn more about how I became interested in the mountain beaver, you can read this article:Mono Basin Discovery!. I hope after you read more about this very special species, you will agree with me that the species is very unique and want to learn more about it.
BASIC
INFORMATION
The mountain beaver is not really a true beaver. It's a little-known but fascinating rodent which occupies a unique taxonomic and ecological niche. It lives underground in burrows and is seldom seen above ground. Most people don't even know it exists. Little is known of its ecology.
Range: Mountain beaver have a limited distribution along the west coast of the United States, from Point Reyes along the coast and the Sierra Nevadas in California, northward along the coast and in the Cascades in Oregon and Washington, and slightly into British Columbia.
Subspecies: There are seven recognized subspecies of mountain beaver, four of which are effectively endemic to California. Two of these, the Point Reyes mountain beaver (Aplodontia rufa phaea) and the Point Arena mountain beaver (Aplodontia rufa nigra), are restricted to very small ranges although considerably more suitable habitat seems to exist. The Point Arena mountain beaver is a federally-listed endangered species.
Identification: The mountain beaver has been described as a large gopher or tailless muskrat. Since they live underground and come out primarily at night, they may live in the vicinity but never actually be seen by humans. Identification is usually made by finding the burrow openings which are about 6 inches in diameter and in groups of several in a small area. Clipped vegetation near the burrow system is another sign. There may also be "haystacks" of drying vegetation near the burrows.
Food: Mountain beaver are strict herbivores and eat just about any type of succulent vegetation available including plants that are often inedible to other species such as nettle, bracken fern, and salal. Plants are also gathered and dried ("haystacking") near the burrow system, probably for food storage and nesting material.
Habitat:
Aplodontia live mostly in areas with dense understory vegetation
such as coniferous forests or coastal scrub.
-->Andy and Robin shared this great set of pictures of a rather bold mt. beaver that visited their garden regularly. Garden Pictures
--> A mountain beaver showed up this June in Lee Vining within the Mono Lake Basin. This adds some new information to the recent discussions regarding a proposed highway widening project nearby too. I received several pictures and other details too and will add them soon.--> I received some excellent photos and supporting information documenting mountain beaver winter activity in the high sierras. The photos show food caches, latrines, snow activity and more. I'll be adding some of the photos to this website soon. Very exciting stuff and many thanks to Tracey and Bruce. High Sierras Winter Mt. Beaver Activity
--> I received requests to help with several students class projects/reports on the mountain beaver. The students had some great questions and generally worked hard on these projects. It was fun to help too! --> I learned that the "boomer" is the mascot of the Toledo High School in Oregon. Thanks to Glenn I now have a very cool t-shirt that shows just how popular mountain beaver have become! --> I was interviewed by a reporter doing an article on the listed Point Arena Mountain Beaver. I also provided photos and other information for several other articles on the species. --> I was contacted to solve a mystery regarding a potential mountain beaver sighting in an unusual location in the Sierra foothills. It turned out to be an escaped guinea pig but was a fun quest. --> I've recently helped several researchers studying mountain beaver in various parts of its home range including southern British Columbia. Several new projects are getting underway or being proposed too. Updates later. --> I had a very large number of contacts from people, mostly in the NW, that observered mt. beavers and wanted to learn more about them and/or determine if they could keep them from causing harm to their property. I received some great new close encounter stories and photos and will be adding them soon. --> I now have several amazing videos of mt. beaver thanks to Steven Miller and "Baldric". I will be adding them to the website once I figure out how to handle streaming video. These videos really help with showing the movements and behaviour of the species and are quite exciting. You can try an early sample but be advised this is a large (4.3 meg) file. --> I've fixed the broken link to the PAMB Final Recovery Plan on the Publications page here. Please let me know if you find any other broken links here too. --> I've added more information to help people who have questions about controlling mountain beaver activity on their property. While there are no guarentees that any of this will work for you, the information comes from experts in Washington. Here's the link: Mountain beaver control information from Washington state Please let me know how this works for you. Also, there's more information on this subject below in the Concerns section.
--> While not exactly a mountain beaver, I've had great fun working with keenly observant Saskia who contacted me about the mysterious "Woody" living on her property in eastern Kansas. We determined this critter was at the very edge on the species range near the state line. Great team detective work and lots of fun!
--> Mountain beaver have been in the news recently as a drastic rollback of Washington state’s voter-approved ban on most animal trapping was vetoed Tuesday by Gov. Gary Locke, who said opponents of the prohibition went too far in overturning voter wishes. The failed alternative would have exempted moles, gophers and mountain beaver, three of the most destructive species, from the trapping ban. Read the whole article here: Rollback of animal trapping ban vetoed
--> Vladimir Dinets, a California based naturalist, has succeeded in his quest to photograph the wiley mountain beaver. If fact, he has gone even farther and captured the animal on film "Quest for Aplodontia". You should really check this out.
--> I've added yet another adventure to go with the recent tales & more great photos from close encounters! Check out my new page on this subject.--> Check out this new link Aplodontia tracks and sign for some great new information and pictures from the Virtual Dirt Time web site in Oregon. Note there are lots of pictures there and it can take some time to download if you don't have a fast internet connection.
--> Check out this new article in June/July 2002 issue of National Wildlife magazine for a very interesting discussion on mountain beaver and other "living fossils"!
--> I am always interested in hearing about observations of this species including natural history, ecology, impacts and other subjects. I would be especially interested in hearing about new locations and/or habitats for the species or areas where the species is no longer found. I've just returned from Mount St. Helens (Mount St. Helens Web Cam) where mountain beaver were apparently known previously from the Spirit Lake area. It will probably be quite some time before the species is found there again but I would greatly appreciate any information you might have on this or other locations.
-->I've also just added a couple of very nice pictures thanks to a certain group of students and their teacher in Wishkah Valley!WHAT MAKES MOUNTAIN BEAVER SO INTERESTING?
Mountain beaver are the most primitive species of living rodents, sort of a living fossil. While their range has decreased from that of the fossil record--probably because of geological and climactic changes primarily--very little appears to have changed morphologically.
Mountain beaver were used in early studies of kidney function because their primitive kidneys lack Loops of Henle and are unable to concentrate urine effectively. Other organ systems have not been well studied.
These are mysterious animals. While foraging can occur at any time, day or night, mountain beaver are primarily nocturnal. Most of their time is spent in underground burrows, coming out only to forage or during the short juvenile migration period when young animals leave the nest to establish their own burrow sites. They are difficult to study so have not been given adequate attention by biologists.
At one time it was thought that mountain beaver were colonial animals because several animals may inhabit a series of interconnected burrows. However, it is now agreed that there is little interaction between animals except for territorial behavior within burrows. Each animal has its own burrow nest area which is connected to tunnels with openings to the outside. It is difficult to determine how many animals inhabit a burrow system since an area riddled with holes may contain only a few animals. It has however been well documented that many other species are often found in mt. beaver burrows. I recently received a photo that is a good example of this as a bushy-tailed woodrat was found sleeping in Aplodontia burrow.
Mountain beaver are not pet material. They can be crotchety, vicious animals and have never been domesticated. When disturbed, they can secrete a thick material from their eyes which has been misinterpreted as tears.
Most people don't know mt. beaver exist and some even continue to question that fact it seems even after they've heard about them. For a funny look at what it can be like to search for mt. beaver, check out this poem!
I have been studying the ecology and distribution of this species for many years (Mt. Beaver Publications). You can also find some interesting mountain beaver links here mountain beaver links.
FLEAS
The largest flea in the world, Hystricopsylla
schefferi, is only known from collections made from mountain
beaver and their burrows, and grows to 9 mm (over 1/3 inch) in length!
The coevolution of these two organisms has never been investigated but,
given the ancient lineage of mountain beaver, may provide some
interesting insights to both. For a fascinating discussion on this
subject and the danger of coextinction, check out this article in Flea
News (vol. 49, pg 566-67). I've also included a similar
discussion from the Journal of Medical Entomology (Vol. 31, no. 6) in
this file.
CONCERNS
In the Pacific Northwest, mountain beaver are considered a pest species by many foresters and gardeners because they are abundant and eat seedlings and young trees. In the NW, many people first discover mt. beaver by finding that they have a new "neighbor" digging in their garden! Under these circumstances, it may be necessary to try to discourage the animal's activities or even relocate it. There are some special considerations whenever this is necessary and you can learn more about them here Mt. Beaver Control Considerations.
However, in California mt.beaver are much more limited in numbers and distribution and considered a species of concern. The Point Arena subspecies is an endangered species (A.r. nigra) living in an approximately 6 mile area. Habitat destruction due to human interaction is a major problem. Among other things, special requirements and precautions are necessary if pesticides are to be used near this species. See this publication, Protecting Endangered Species Interim Measures for Use of Rodenticides in Mendocino County, and work with an experienced wildlife biologist. Disasters have exacerbated habitat disturbance in some cases, for example, a recent fire started by campers in Point Reyes destroyed about 50 percent of the known habitat of the entire subspecies found only at that location. Studies are currently underway to determine the extent of damage to the population. There is a very interesting article in the Sept. 2001 issue of Sierra Legal Defence Fund in Canada about how local action prevented the destruction of one of the few known population sites in British Columbia where the species is considered rare.
Photo of a Mountain Beaver (by Dr. Lloyd Ingles)
More very unusual mt. beaver pictures!
I get a surprising number of contacts from people who want to learn more about mt. beaver after discovering them in some form. Most of these contacts come as a result of a web search which locates this web site, one of the few available on this species. If you find other parts of the site not working please let me know and I'll try to get them fixed as quickly as possible.
I'm very interested in mountain beaver observations or questions and would like to hear from you. dalet.steele@gmail.com. If I'm online, you can contact me directly by sending an instant message on Yahoo at daletsteele too.
Dale Steele
P.O. Box 162644
Sacramento, CA 95816
(916) 698-1146
(Pay attention to the open skys, you never know what will be coming down....)