Did you know that the beaver is actually a rodent? The beaver is the largest rodent in North America. They are built for living in the water: short, with stout legs and a large, flat, nearly hairless tail that they use to maintain balance while gnawing on trees. Beavers will use their tail to warn other beavers by slapping it against the water, making a big “smack!” sound. Their front feet have heavy claws, and their hind feet are webbed, which propel them through the water when they are swimming. When the beaver is under water, its nose and ears close up and a special membrane covers its eyes. Beavers have long sharp upper and lower incisor teeth that they use to cut into trees and woody vegetation. These teeth grow throughout the beaver's life.

© 2009 Elizabeth A. Sellers, Courtesy of

Habitat: Beavers live in the water, so they can be found in streams, small ponds, lakes, and rivers. They build their homes, or “lodges,” out of sticks and mud on islands, pond banks, or on lake shores. Some beavers will build burrows in the banks of rivers.  You can often see Idaho beavers in the morning or evening, when they are most active. 
Beavers mostly eat tree bark and cambium, the soft tissue that grows under the bark of a tree. Their favorite trees include willow, maple, birch, aspen, cottonwood, beech, poplar, and alder trees, but they will also munch on other vegetation such as roots, buds, and water plants.  

beaver in water 
A beaver swimming  

Fun Facts: Beavers mate for life, but if one mate dies, the other will find another mate. Females have one litter of “kits” per year. Beaver kits are born with their eyes wide open and can swim within 24 hours.    

beaver dam
Credit: John J. Mosesso /


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Herbivore Mammals

Pygmy rabbit 
Desert cottontail 
Eastern gray squirrel 
Red squirrel 
Deer mouse
Kangaroo rat 
Meadow vole 
Mule deer 
Bighorn sheep 
American pronghorn 

Carnivore Mammals

American badger 
River otter 
Red fox 
Long-tailed weasel 
Grizzly bear 
Mountain lion   



  Long-toed salamander 
  Idaho giant salamander  
  Coeur d'Alene salamander

 Frogs and Toads  

  American bullfrog 
  Columbia spotted frog 
  Western toad 
  Northern leopard frog 
  Pacific tree frog 
  Great Basin spadefoot 



Painted turtle 
Northern alligator lizard 
Mohave black-collared lizard 
Short-horned lizard 
Desert horned lizard 
Sagebrush lizard 
Western fence lizard 
Western skink 
Side-blotched lizard 
Longnosed leopard lizard 
Western whiptail 



Western pipistrelle 
Western small-footed myotis 
Little brown bat 
Yuma myotis 
Townsend's big-eared bat 
Hoary bat 
Silver-haired bat 
Fringed myotis 
Pallid bat

Sensitive Species (not a complete list) 

Greater sage-grouse 
Pygmy rabbit 
No. Idaho ground squirrel 
So. Idaho ground squirrel
Canada lynx 
Grizzly bear 
Selkirk Mtns. woodland caribou 
Kootenai White River sturgeon 
Bull trout 
Sockeye salmon 
Chinook salmon 
Steelhead trout 
Yellow-billed cuckoo