Beavers:
* Rodent Family: Castoridae
* Size: Large, typically weighing 30-70 lbs
* Habitat: Near water, build dams and lodges
* Diet: Primarily trees and shrubs
* Key Features: Webbed hind feet, flat, paddle-like tail, prominent incisor teeth
* Behavior: Highly social, live in family groups, known for building dams and lodges
* Distribution: North America (Canada, USA) and Eurasia
Mountain Beavers:
* Rodent Family: Aplodontiidae (only family in the order Aplodontia)
* Size: Small, weighing 1-2 lbs
* Habitat: High-elevation forests, primarily in the Pacific Northwest of North America
* Diet: Primarily grasses and other vegetation
* Key Features: Short, thick body, small ears, no visible tail, short legs
* Behavior: Solitary, burrowing, less social than beavers
* Distribution: Western North America (Pacific Northwest region)
Here's a table summarizing the differences:
| Feature | Beaver | Mountain Beaver |
|---|---|---|
| Family | Castoridae | Aplodontiidae |
| Size | Large (30-70 lbs) | Small (1-2 lbs) |
| Habitat | Near water, build dams and lodges | High-elevation forests |
| Diet | Primarily trees and shrubs | Primarily grasses and other vegetation |
| Tail | Flat, paddle-like | No visible tail |
| Behavior | Social, build dams and lodges | Solitary, burrowing |
| Distribution | North America and Eurasia | Pacific Northwest of North America |
In essence, beavers are much larger, live near water, and are known for their dam-building abilities. Mountain beavers are smaller, live in forests, and are solitary animals with no tail.