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Native Californian, biologist, wildlife conservation consultant, retired Smithsonian scientist, father of two daughters, grandfather of 4 small primates. INTJ. Believes nature is infinitely more interesting than shopping malls. Born 100 years too late.

Thursday, July 31, 2008

The seldom seen showtl (or aplodon)

I set four camera traps in Sierra county a month before the camera trapping workshop, and was mighty pleased to find that mountain beavers -- hereinafter show'tls or aplodons -- occur in the drainages feeding the Yuba river.

Yes, from here on out I am calling them "aplodons" or "showtls". They deserve a catchy vernacular tag or a name (like "simple teeth") befitting their unique evolutionary position.

Let's forget the term "mountain beaver". Yes, like beavers they are excellent swimmers and waterway engineers, but there the resemblance ends. The name boomer doesn't cut it either. The only report of such a sound is now over 130 years old.

Then there's the name "sh'auch" used by the Indians of Puget Sound. It meant "creature that creeps in the undergrowth", and you can guess why that didn't take. The other moniker -- "sewellel" -- is said to have been the Indian term applied to robes made of their furs.

Enough. Back to the workshop. . .

When it commenced on July 21, the cams had been in the field for a month. Knowing that camera trapping is often slow business, I wanted to fire up the class at the outset by showing them the seldom seen showtl.

The gamble paid off. After I had rambled at length the first morning about camera trap sets and camera attachment methods, we climbed into the nearby thicket, found the cam, and clicked through the pictures.

A beady-eyed rodent finally appeared in the LCD, and being topless, she disclosed her sex within the first few pictures (notice that I don't confuse sex with gender). We didn't realize this until she was displayed on the computer screen.

The fact that she was bare-breasted has special significance. Female aplodons have very hairy nipples when cycling, pregnant, or lactating. We're talking about "dense patches of black hairs". Though a sign of showtl womanhood and of certain adaptiveness, it is not an enviable trait. It's likely that this bare-nippled girl was born this spring.

Aplodon colonies in this part of the sierra are in sprawling alder thickets bordering the Yuba river and its tributaries. We found numerous nipped twigs of alder, but the pruned stubs were dry and gray. I was almost convinced that alder is a springtime food until we found a burrow with leafy wilting branches.

Lewis and Clark were the first to report on aplodon's climbing ability, but University of California mammalogists Joseph Grinnell and Tracy Storer had their doubts. Lloyd Ingles proved it with photography.

Ingles built an enclosure at Huntington Lake in the southern sierra, and stocked it with two females from a nearby colony. They climbed 20 ft up into white firs and lodgepole pines, and in 4 weeks pruned off most of the branches. Aplodons are respectable if not acrobatic climbers of trees and shrubs, but they have to descend butt-first.

I thought that aplodons would be easy pickings for the workshop participants, but I was wrong. No one else got their photos.

When I checked the date and time stamps on my own pictures I realized why. The animal had visited the burrow only on three occasions, and the first visit wasn't until three weeks had passed. Aplodons have extensive burrow systems with multiple openings.

During the course I tried to get more photos by planting my small camera traps in underground tunnels with caved in ceilings. Every sign indicated they were active tunnels, but no aplodon showed it face.


Camp, C.L. 1918. Excavations of the burrows of the rodent Aplodontia, with observations on the habits of the animal. Universitu of California Publications in Zoology 17(18):517-536

Godin, A. J. 1964. A review of the literature on the monjtain beaver. Special Scientific Report -- Wildlife No. 78. U.S. Department of the Interior, Fish & Wildlife Service, Bureau of Sport Fisheries and Wildlife, Washington D.C.

Ingles, L.G. 1960. Tree climbing by mountain beavers. Journal of Mammalogy, 42(3):120-121

Scheffer, T.H. 1929. Mountain beavers in the Pacific Northwest: their habits, economic status, and control. US Department of Agriculture, Farmers' Bulletion No. 1598:1-18


Beverly said...

Oh my…sometimes your blog makes me soooooooo homesick! I do love Colorado (and four seasons), but sometimes I ache for the ocean; cool, salty air and beaches. [sigh]

I used to especially love Point Reyes (and Big Sur, too) and remember once spending a romantic weekend at the Holly Tree Inn there…and dining on local shellfish at the Olema Inn, in nearby Olema. OMG…a meal to die for! If you’re able to take your redhead on such a trip, do…and stay at the Inn. I wonder if it’s owned by the same people some 30+ years later…but the location itself was a delightful place to stay.

I love that mix of ocean and forest…

Wonderful story and photos; I'd never even heard of a 'mountain beaver'! Odd, too; sometime you'll have to look up the name 'Beverly'. ROFLMAO

Camera Trap Codger said...

We know the Marin coast well, Beverly, but the prices in those joints are out of sight these days. So it's usually peanut butter sandwiches while parked by the Bolinas lagoon watching shorebirds, waterfowl, and seals.

Hugh Griffith said...

Fun! These are among my favourite creatures. What that says of me I'm not sure I want to know. Thanks for a very interesting post (including the link to your earlier post).

Anonymous said...

"The Mammals and Life Zones of Oregon" (1936) by Vernon Bailey also gives the name "Mountain Burrower" (which I kind of like). Also the name "Netate" from the Telowa tribe of Crescent City.

I got a photo of one of these once (with a camera trap) that had a fairly large parasite on it.

As always, thanks for sharing.

Anonymous said...

Nice photos. We used to have quite a few mountain beaver near our home in Gig Harbor, WA (about 1980). I don't think they are too sharp about what is going on around them - maybe bad eyesight or hearing. So we never used to have coyotes. Then they showed up in the 1990's. Alas, no more mountain beaver sightings.