There's a good chance you've never seen a Mountain Beaver before. Or even heard of it, for that matter. But the truth is, it's got quite a backstory.
Mountain Beavers are the world's most primitive species of rodent, dating back more than 25 million years.
They're often called the 'Living Fossil' and they live in Canada, in the mountains of British Columbia.
Trouble is, there aren't many of them left. No one knows the exact number. But in 1999, researchers found 634 occupied nests in southern B.C.
Logging is the biggest threat to the mountain beaver, because the heavy equipment presses the earth together - making it tough for them to dig their dens.
Plus, we keep expanding where we live and end up closer and closer to their habitat. Throw in climate change and the mountain beaver is having a rough go of it.
Because they're a primitive species, mountain beavers are sensitive to heat and drought. So as temperatures rise, they're in more danger.
In fact, if it's a really hot day - more than 32 degrees - and they're in the heat for more than a few hours, they can die.
Mountain Beavers originally lived throughout North America. But eventually ended up in Pacific Northwest, where the forests are cooler.
They don't have much in common with the North American Beaver. They don't build dams; they live in dens in the ground. And their tails are short and stubby, not big and flat.
Right now, the Mountain Beaver is considered a species of special concern.
The Committee on the Status of Endandered Wildlife in Canada wants it to stay that way.
But it's up to Environment Minister Peter Kent. Last week, he denied this status to three other species. You can read about that here.