SciSun: The Unknown Fossil   Leave a comment

Beavers, as everyone knows, are large, water-loving animals that live in mountain forests; cut down trees by gnawing on them; drag the logs through the water to build dams and lake-view houses; eat the smaller twigs and branches that are too tasty to use as construction material; have flat tails, webbed feet, two very large front teeth; and are often seen, in cartoons, wearing construction helmets. (Which, on that last point, we find hard to believe as construction helmets are only available in those smaller sizes by special order and UPS won’t deliver into the forest). But not all beavers are created equal; actually, some ‘beavers’, aren’t really beavers at all – at least not in the way we would expect a beaver to be.

The Mountain Beaver (Aplodontia rufa) is, like its well-known counterpart, a large rodent that lives only in North America. Unlike its namesake, it does not cut down trees for construction; does not particularly like to swim nor be in water; does not have a flat tail (or much of a tail at all); is never seen in cartoons; and isn’t even usually found only in the mountains but lives among meadows and forest edges . It is known by other names, though just as confusing as ‘Beaver’: Giant Mole (which is no relation); Ground Bear (which could be understandable for someone who isn’t quite certain what a bear looks like); Boomer and Whistler (odd, as the animals make neither whistle, nor booming noises). Perhaps the most appropriate, though little used name, is the Native American Sewellel, meaning fur coat – which says more about how the animal was viewed, than about the animal itself. But we think the name sounds like ‘swell’, so we’ll just think of it as pretty unique and awesome.

Although typically camera-shy, Mountain Beavers are not opposed to looking exceptionally cute.

Although typically camera-shy, Mountain Beavers are not opposed to looking exceptionally cute.

Not only is this swell animal generally unseen and largely unknown, they are the only living members of the ancient family Aplodontidae, the most primitive of all rodents, and its age shows in teeth patterns; digestive system; and physiology that’s less complex than their more-recent rodent cousins. As rodents were among the first of all mammals, the Mountain Beaver is a living connection to a world long-gone and could hold clues on evolution, adaptation, survival, and other questions that scientists are asking about our ever-changing planet; the answers which could result in medical and environmental innovations. Living in the Pacific Northwest and parts of the Sierra Nevada mountains, M. Beaver (not be confused with J. Beiber) remains private and elusive (again, nothing like J. Beiber); and one sub-species of this group, the Point Arena Mountain Beaver (Aplodontia rufa nigra) is an officially designated rare and endangered species found only within a 24-square mile area of California. As underground burrow dwellers, the animals are vulnerable to human construction, development, recreation, and even livestock movements that disturb and destroy land and vegetation. Over thirty million years of adaptation has equipped them with highly developed sound, smell, and touch necessary for sensing when a predator is in the area, but can be disorientating and stressful when trying to interpret the meaning – and dangers – of construction equipment; herds of cattle; and off-road ATV’s.

Today, no one knows how many Point Arena mountain beavers remain, or exactly where they live and how sensitive the entire population is to ecological – or man-made -changes to their home. So secretive that often the only signs of their presence are carefully hidden burrow entrances; footprints; and enough eaten plants – particularly herbs and flowers that humans also enjoy – that the animal is sometimes considered a pest and mistaken for a gopher, mole, or rat and not the unique and prehistoric life – sometimes considered a ‘living fossil’ – it is. After millennia of survival, M. Beaver just isn’t getting his due respect. Maybe it’s time for a talk show tour. Or at least a cartoon, and little construction helmet.

http://www.fws.gov/arcata/es/mammals/mtnBeaver/mtnbeaver.html

http://www.nps.gov/pore/learn/nature/mountain_beaver.htm

^^^

Michonne Says: I’ve seen a lot of animals, but I don’t remember ever seeing one of these Mountain Beavers. They kind of look like a marmot, so maybe I have seen one and didn’t recognize her. Next time I’ll have to ask, but I don’t want to look like I can’t tell a marmot from a beaver. That would just be embarrassing.

Posted October 4, 2015 by ECOVIA eco-adventure® in SciSun

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