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ID Characteristics
Funky Facts!
References/More Information 

aquatic mammals


Beaver (Castor canadensis):

Beavers have shorter front legs then their back, and their back feet are webbed. The front feet have thick claws. Beavers have a long, thick hairless tail that they will smack on the surface of the water to deter predators away from their dams. 


  • In parks along the river such as Oxbow, you may see felled or damaged trees, or trees with chicken wire around the base. These are signs of beaver activity which is probably the most you will see of these mainly nocturnal creatures. 

  • Chicken wire is wrapped around the base of trees to prevent beavers from cutting down too many trees such as cottonwoods that are important for riparian habitat for other species. 

  • Beavers live in family groups with parents and offspring until the offspring mature to around 2 years in age when they leave to start a new family unit. 

  • The largest rodent in the Great Basin range is the beaver. 

  • Beavers range from around 30-60 pounds when mature. 

“Geologic and Natural History Tours in the Reno Area” Nevada Bureau of Mines and Geology. 

PBS: Nature Tours, “Beaver - Castor canadensis.

American Mink (Neovison vison):

American Minks have long slender bodies that are around 2 feet in length with short legs and semi-webbed toes. These minks have dark glossy fur usually with a patch of white under the chin.

  • American Minks are carnivores and can dive to depths of 5-6 meters (that’s around 16-20 feet) to catch prey, even though they are considered only partially aquatic!

  • These minks can climb and jump between trees and even run down trees head first.

  • American Minks communicate via visual, auditory, and chemical cues. They mark their territory by secreting a musky scent from anal glands that communicate to other minks that the area is reserved.

  • Minks will kill a surplus of food and store the excess which can, in some places where they were introduced, have a negative impact on the environment (outcompeting other predators and over hunting prey).

  • American Minks are one of the most prized furs and they are bred on fur farms to supply this demand. Some of these minks escape from the farms and establish a population where they are normally not found, sometimes outcompeting many native species. These escaped domesticated minks can also mate with wild minks potentially causing their descendants to be less adapted to the wild.

Wildscreen Arkive: American Mink.

Animal Diversity Web: Neovison vison.


land mammals

California Ground Squirrel (Spermophilus beecheyi):

The coat of the California Ground Squirrel is a mottled mix of gray and light browns. The belly of this squirrel is beige and has a yellow tinge.

  • California Ground Squirrels communicate through scent, tail movements, and verbal screeches which they use to warn other squirrels of danger.

  • These squirrels live in colonies in burrows that can house multiple generations, but each squirrel has its own burrow entrance.

  • California Ground Squirrels are usually never more than 150 yards away from their burrow entrance.  

California Ground Squirrel.” NatureMapping, NatureMapping Animal Facts.


Animal Diversity Web: “Spermophilus Beecheyi (California Ground Squirrel).” University of Michigan, Museum of Zoology by Lima, Marcie. 


American Black Bear

(Ursus Americanus):

black bear

American black bears come in a variety of colors despite their name. These bears range in shades from black to blonde and even white in northern latitudes. They differ in appearance from grizzly bears in that they have long ears, convex face profile, smaller claws, and a pale-colored nose. The average weight of a black bear is about 150 - 250 pounds, but this will vary based on sex, season, and food availability. 

  • Black bear behavior stems from the availability of food sources. When food is abundant, groups of bears will congregate and be social, but when food sources are sparse, bears are more solitary and may be more defensive of territories. 

  • Black bear’s diets are mostly made up of fruit, nuts, insects, and plants. When bears do eat meat, they prey on young mammals and birds, leaving the adults alone. 

  • Black bears can run up to 30 miles per hour! However, they usually use that speed to escape danger and not for hunting. 

  • Female black bears give birth to cubs and then enter hibernation. The cubs do not hibernate during the mother’s hibernation so they can feed and stay warm. The cubs grow from about 0.5 pounds to about 11 pounds over the winter!

  • Black bears are the smallest of the three bear species in North America, the other two species being grizzly bears and polar bears. 

  • In order to sustain itself during the winter, a black bear will consume 20,000 calories in an attempt to add almost half its body weight. 

Nevada Department of Wildlife: Black Bear 

National Geographic: American Black Bear 

Bear Smart: About Black Bears

“The Smithsonian Book of North American Mammals” by Don E. Wilson and Sue Ruff


Bobcat (Lynx rufus):


Bobcats are brownish in color with black spots and stripes and a white belly. Their ears are topped with a tuft of black fur with a white spot on the back. Bobcats have the eponymous short, “bobbed” tail. The cats weigh about 20 pounds. 

  • Bobcats are habitat generalists and can be found in many places in northern Nevada including deserts, forests, swamps, and even in neighborhoods near their home ranges.

  • Bobcats will prey on animals as small as mice and as large as deer. They have been known to eat fish, reptiles, birds, insects, small mammals, and some vegetation. 

  • Bobcats have been observed ambushing deer by dropping out of trees onto the passing animal. The deer can weigh up to 8 times heavier than the bobcat!

  • Bobcat den sites are usually rocky areas where around 3 kittens will be born. The cats will also use caves, dense vegetation, or fallen logs for cover and shelter. 

“The Smithsonian Book of North American Mammals” by Don E. Wilson and Sue Ruff

Animal Ark: Bobcat

Mountain lion (Puma concolor):

mountain lion baby.jpg

Mountain lions have medium brown colored fur (“concolor” from their scientific name is latin for “one color”). The cats measure up to 9 feet in length from nose to tail and weigh up to 200 pounds.

  • Mountain lions have a large home range extending from Canada all the way to Mexico. The cats have many different regional names including cougar, puma, panther, painter, and catamount. 

  • The lions are solitary except during the mating season. Female cats will vocalize with whistles and screams and leave scents to lure males. Kittens will stay with their mother for about a year then transition to solitary life after learning hunting and survival skills. 

  • Mountain lions eat mainly deer and deer habitat is usually an indicator of mountain lion habitat. They will also feed on some birds and small rodents. Grass has been observed in mountain lion scat and is believed to be a digestive aid. 

“Big Game of North America” by Edwin A. Bauer

National Wildlife Federation: Mountain Lion

Don't Feed the Bears!

Black bears can easily become accustomed to human food, typically going through human garbage and in rare occasions have entered residence in search of food.


Unfortunately, when a bear becomes accustomed to finding food near humans, there is a chance they will be relocated but often times they are killed due to the risk they pose, so please do not feed the bears!


Yellow-bellied Marmot

(Marmota flaviventris):


The yellow-bellied marmot looks like a big, stout squirrel. They can grow up to 11-inches in length and weigh up to 11-pounds. Their fur is a brownish-reddish color with a yellow belly. The yellow-bellied marmot is found in high elevations and close to rocks.

  • Yellow-bellied marmots hibernate up to eight months a year. This means they only have a short amount of time to mate, raise their young, and fatten up for the next winter.

  • Due to their love of rocks, yellow-bellied marmots are often referred to as ‘rock chucks’.

  • When they aren’t busy eating or cleaning, yellow-bellied marmots like to sun bathe on top of rocks. 

  • Their burrows are extensive, when the yellow-bellied marmots are no longer using the burrow, other animals take them over.

Wildlife Land Trust: Yellow-bellied Marmot.


National Wildlife Refuge: Yellow-bellied Marmot by Lee Metcalf.

Rocky Mountain National Park: Marmot.


Coyote (Canis latrans):


Also called a prairie or bush wolf, coyotes are generally around 24 inches tall at the shoulders, and weigh an average of 40 pounds. Coyotes have narrow elongated snouts, their fur is very long and course, and their tails are bushy and usually black tipped. They vary in color from red, grey, and black, and their bellies are typically white in color.

  • At the turn of the 21st century the coyote population was at its highest point. Since the wolf population has dropped significantly in the United States over the last 150 years, this has allowed coyotes to thrive. Wolves kept the population of coyotes regulated to what is now the central United States and Northern Mexico, but since the coyotes no longer had wolves as competition, they can be found almost everywhere in North America. 

  • Coyotes are very opportunistic eaters, they will eat anything from frogs and snakes to something as large as a deer. They are happy to snack on insects like grasshoppers as well! 

  • Part of the coyotes’ resilience is its ability to adapt to humans. While urbanized coyotes do not fear humans, they generally stay away from them. It's not uncommon however to find packs in major cities like Chicago and Los Angeles (they are also fairly common in and around Reno). Coyotes are attracted to cities due to ease of food as they can go through garbage and hunt small prey including domestic dogs and cats.

National Audubon Society: Field Guide to Mammals by Alfred A. Knopf  


Britannica: Coyote 

National Geographic: Coyote


Brazilian Free-Tailed Bats

(Tadarida brasiliensis):

Brazilian Free Tailed Bat

Medium sized bats with distinctive short snouts and wrinkled upper lips. These bats are most easily recognized by their “free-tail,” which extends well beyond the end of their body.

  • Brazilian free-tailed bats are aerial insectivores that use echolocation to catch flying insects while they, too, are in flight!

  • These bats excrete guano, which can be harvested as a fertilizer but can also pose a health risk by spreading diseases that are transmitted through the air (Histoplasmosis).

  • Predators include red-tailed hawks, American kestrels, great-horned owls, and raccoons.

Animal Diversity Website: Tadarida brasiliensis


Wild Horses (Equus ferus):

Wild horses hidden valley.jpg

Wild horses vary in color and pattern. Most wild horses are 52-60 inches tall and weigh between 700 and 1000 pounds.

  • The Bureau of Land Management (BLM) manages and protects wild horses under the Wild-Free Roaming Horses and Bureau Act of 1971. 

  • To control overpopulation, the BLM has implemented an adoption program.

  • As of March 1, 2020, the BLM estimates a total nationwide wild horse and burro population of 95,114.

  • Wild horses are descendants of domestic horses, and have adapted to the Western range over hundreds of years. 

  • Nevada is home to over half of the wild horses protected by the BLM. 

  • It is illegal to feed horses. Please keep your distance; these horses are wild, and thus, untrained, and can be dangerous.

BLM: Wild Horse and Burro Program


local resources

Check out these organizations to learn more about mammals in our area!