‘Living fossil’ resident of Lake Tahoe Basin
December 10, 2003
By Gregory Crofton
Tribune staff writer
Jenni Jeffers has spent the last two summers at Tahoe studying a rodent that’s been on the planet for 40 million years.
The mammal – so old that biologists recognize it as a living fossil – is only found in the United States at higher elevations in Nevada, California, Washington and Oregon.
It needs to live near running water because its kidneys are archaic and not able to retain it, said Jeffers, a diversity biologist for the Nevada Department of Wildlife.
Called mountain beavers, the foot-long creatures weigh only a couple of pounds. They live around Lake Tahoe and at other select locations in the Sierra Nevada. Their population is limited but not considered endangered by state or federal wildlife biologists.
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Jeffers said it was 1946 when a biologist from Nevada last studied the state’s population of mountain beaver, which is confined to the Lake Tahoe Basin.
From her studies, which began in 2002 and are ongoing, she estimates a couple of hundred of the animals live on the Nevada side of the lake. Jeffers described the population of mountain beaver at Tahoe as one that’s “hanging on.”
Out of the three locations where mountain beaver were found in 1946, Jeffers found two populations still in existence.
The other place, at Incline Village, “is now a Tahoe center, with a golf course, houses and ditches,” Jeffers said.
Mountain beavers live in burrows near running water; but they don’t swim or make dams. An American beaver can live 20 years and has a large flat tail. Mountain beavers live about five years, have a stubby tail and thick claws to dig with.
“It’s not a true beaver at all,” Jeffers said. “But it’s vocalization is similar to an American beaver. They growl, hiss and whine.”
Mountain beavers can also climb trees; have thumb-like appendages that help them hold an apple like a raccoon would; and can stomach poisonous plants, said Dale Steele, supervising biologist at the California Department of Fish and Game.
“I’ve seen one 15 feet up in pine,” Steele said. “They don’t look like them but from studies over the years (we know) they are the ancient living ancestors of squirrels and chipmunks.”
Jeffers said when her study is complete one goal would be to establish a conservation strategy for the animal. Right now few people even know it exists because they spend about 90 percent of their lives underground.
“There’s been a lot written on how ferocious they are. That they can grab and hold on and crush with their jaw,” Jeffers, who noted that a mountain beaver feels like solid muscle. “But if you’re handling them and you’re very quiet and don’t do anything to hurt them, they’re fairly docile.”
– Gregory Crofton can be reached at (530) 542-8045 or by e-mail at email@example.com