30 Types of MAMMALS Found in Alaska! (2023)
Do you want to learn about the mammals that live in Alaska?
Luckily, you’ve come to the right place!
I have compiled a list of the most common and interesting mammals in Alaska, with photos, facts, and RANGE MAPS. As you will see, there are lots of species, each with different and interesting habits and traits.
And, if you want even more information about mammals, or need help with additional identification, check out this field guide!
Here are 30 types of MAMMALS found in Alaska!
#1. American Black Bear
- Ursus americanus
- Adults range from 5 to 6 feet tall and weigh 200 to 600 pounds.
- Coloration ranges from mostly black on the east coast to brown, cinnamon, or blonde in the west, and blue-gray or even creamy white in some populations.
- They have a flat back, small head, rounded ears, and non-retractable claws.
American Black Bears occupy various habitats in Alaska but generally prefer inaccessible terrain.
Black bears are sometimes considered a nuisance because they sometimes damage cornfields, honeybee hives, and berry farms. In addition, they’re easily attracted to garbage, bird feeders, and coolers. Make sure to NEVER feed them, as this can make the bear not afraid of humans, which is dangerous for both people AND the bear.
Generally, Black Bears are timid around people. Unlike grizzly bears, females with cubs rarely attack people, often just sending their cubs up a tree so that they can retreat safely.
Black Bears are naturally active in the evening and early morning but sometimes alter their activity patterns for food availability. Bears may become active during the day when garbage and other human food sources are available. Black Bears in campgrounds often develop nocturnal activity patterns.
Despite the common belief, Black Bears in Alaska don’t truly hibernate.
Instead, they enter a state of shallow torpor. In this state, their body temperature decreases, their metabolism slows, and they don’t need to wake to eat, drink, urinate, or defecate. Consequently, Black Bears must put on a heavy layer of fat in the fall to survive through winter and spring.
#2. Brown Bear (Kodiak/Grizzly)
- Ursus arctos
- Adults are between 3 to 5 feet tall on all fours or up to 9 feet standing on hind legs and weigh 200 to 1,000 pounds.
- Coloration can range from black to blonde.
- They have a distinct shoulder hump, disc-shaped face, and long claws.
Brown Bears, Grizzly Bears, and Kodiak Bears are a single species, Ursus arctos. The term Brown Bear often refers to those that live on the coast. Bears that live inland are often smaller and generally referred to as Grizzlies. Kodiak Bears (Ursus arctos middendorffi) live on the Kodiak Archipelago and have been isolated from mainland populations since the last ice age, about 12,000 years ago.
All three share the same basic physical characteristics; for this guide, we will call them Brown Bears. They occupy various habitats, including desert edges, high mountain forests, ice fields, tundra, alpine meadows, and coastlines. They prefer areas with dense cover in which they can shelter. Before the arrival of European settlers, Brown Bears were also found in the Great Plains.
Brown Bears are normally slow, but if needed, they can run at speeds up to 35 miles per hour! They also swim as they prey upon fish or cross rivers. Unlike the black bear, adult Brown Bears generally aren’t adept at climbing trees due to their size and weight. However, they have an excellent sense of smell, which they use to locate food.
Brown Bear populations are drastically reduced from their number before the westward movement of European settlers. Some estimates indicate that Brown Bears now occupy just 2% of their former range. Today, they face threats from habitat destruction due to logging and mining and the development of roads, subdivisions, golf courses, and resorts.
#3. Polar Bear
- Ursus maritimus
- Adults range from 7 to 8 feet in length and stand up to 11 feet tall.
- Their outer layer of fur is hollow and white, and they have a black nose.
- They have strong legs and large flattened feet with slight webbing.
Polar Bears are the largest carnivorous mammal in Alaska.
They’re found in the far north and spend most of their time on sea ice, only coming to land to breed. Polar Bears are also excellent swimmers and frequently travel between ice islands, especially during periods of ice breakup.
These large carnivores feed almost exclusively on Ringed Seals but will also prey on Bearded Seals. They wait for seals to come to the surface to breathe and then pull them onto the ice. Polar Bears occasionally feed on whale and walrus carcasses and bird eggs, but these food sources are not abundant enough to sustain them.
Sadly, Polar Bear populations are declining, and scientists fear they are in danger of extinction. Climate change is causing a loss of their sea ice habitat. In some southern areas, like Hudson Bay, there is no longer sea ice in the summer, meaning that the bears eat little or nothing all season. In addition, female Polar Bears in these areas are no longer able to breed successfully, meaning these populations will eventually die out.
- Alces alces
- Adults stand about six feet at the shoulder and weigh more than 1,000 pounds.
- Their coloring is generally dark brown. Cows (females) have a light brown face and a white patch of fur beneath the tail.
- Moose have flaps of skin called dewlaps hanging from their throats, and bulls (males) grow massive antlers up to six feet across in the spring and summer.
Moose, the largest member of the deer family, only thrive in colder climates due to their massive size and insulated fur. Their hair is hollow, helping to trap air and provide maximum insulation. Their ideal habitat includes a mix of mature and young trees, which provides abundant forage.
I was surprised to learn that Moose are named for their diet! The word “moose” is an Algonquin term that means “eater of twigs.” They feed on woody material from trees. During the summer, they also eat large quantities of aquatic plants. A single moose consumes 25 to 45 pounds of vegetation per day.
Female Moose, called cows, are known to aggressively defend their young, which often have a high mortality rate until they turn one. Mothers have been known to injure or kill grizzly bears, wolves, black bears, and even people in defense of their babies. If you come across a Moose with babies, stay as far away as possible to avoid injury.
Moose are highly susceptible to the effects of climate change. Warmer winters have resulted in higher tick infestations, causing Moose to die of blood loss and anemia. Tick infestations are believed to be the main cause of Moose populations dropping 40% in the last decade.
#5. Mountain Goat
- Oreamnos americanus
- Females weigh 125 to 180 pounds.
- Males weigh between 135 and 300 pounds and have a more developed chest.
- They have white coats, split hooves, and shiny black horns.
Mountain Goats spend most of their time at high elevations above the tree line, often exceeding 13,000 feet above sea level. They move to lower elevations to access salt licks, seek cover, or find available forage. They are the least studied large mammal in Alaska due to their remote, high-altitude habitats.
These mammals are herbivores and spend most of their time grazing on grasses, mosses, lichens, twigs, and leaves. They are ruminants with four-chambered stomachs. This feature allows them to eat quickly and then regurgitate, re-chew, and slowly digest their food to break down tough plant matter.
One of my favorite things about Mountain Goats is the nicknames for males, females, and babies! Nannies (females) and billies (males) have extensive mating rituals that last weeks. Billies stare at nannies, paw “rutting pits,” and get into showy fights that sometimes result in injuries. After mating, the sexes separate for most of the year. The billies split off into smaller bachelor groups of just two or three individuals, while the nannies form large nursery groups, which include the babies, or “kids.”
#6. Dall Sheep
- Ovis dalli
- Adults stand about 3 feet high at the shoulder, and males are noticeably larger than females.
- They have thick off-white fur that consists of coarse, stiff, hollow guard hairs and a fine wool undercoat.
- Both sexes have horns, but the males are large, thick, and curled, while the females tend to be smaller, slender, and slightly curved.
Dall Sheep are found in arctic and sub-arctic regions with steep, rugged cliffs and rock outcrops. This rugged terrain helps them to evade predators. During the winter, Dall Sheep prefer locations with low snowfall and high winds that expose plants to forage.
For most of the year, ewes (females) and rams (males) live separately. Adult rams form bands of bachelors while the ewes live in flocks with other ewes, lambs, and immature rams. The rams even form social hierarchies within their bachelor band during the summer. As you could probably guess, rams with the largest horns are the highest in the social order.
When males and females come together for breeding, violent dominance displays between rams often occur. Kicking, dominance mounting, and jumping are common, and they also engage in horn clashes where they run at each other and smash horns. They’ve even been known to push each other off of cliffs!
#7. Mule Deer
- Odocoileus hemionus
- Adults are 4.5 to 7 feet in length and weigh between 130 and 280 pounds.
- Their coloring is tan to brown in summer and brownish-gray in winter, with a light gray face and distinctive black mask.
- They have large ears and white tails that are black at the tip, and males have branched antlers.
Mule Deer, named for their big, mule-like ears, are iconic mammals in southern Alaska. They’re found in rocky, arid environments and thrive in areas with a mix of early-stage plant growth and diverse shrubs.
This species feeds on trees and shrubs rather than grasses. Unlike cattle and Elk, which eat large quantities of plant materials with relatively low nutritional value, Mule Deer are selective. They prefer to feed only on high-quality young plants to thrive.
Mule Deer are social animals. Females tend to stay in multi-generational family groups. Bucks leave the family group after a year and are solitary or travel in small groups with other bucks. Family groups sometimes join to form a larger herd for greater protection in the winter.
#8. Caribou (Reindeer)
- Rangifer tarandus
- Adults range from 4.9 to 7.5 feet in length.
- Their coloring varies widely by location and season, from very dark brown to nearly white.
- They have large, broad hooves, and both males and females have antlers though the males’ are much larger and more complex.
Caribou, which are also called Reindeer, inhabit arctic and subarctic tundra regions and migrate with changing seasons. They usually follow the same routes yearly but sometimes change patterns unexpectedly to access areas with more food. They may travel more than 3,100 miles in a year!
These social animals gather in large herds of tens of thousands of individuals during the calving season. The large numbers provide relief from insects and protection from predators like wolves and bears, which prey on young calves. In the winter, Caribou tend to break into smaller herds.
In late August or September, males shed the velvet from their antlers and prepare to compete for females during the rut. They engage in battles that can result in exhaustion, injury, or death. Dominant males may breed with as many as 5 to 15 females. The males usually stop eating and lose much of their body fat during mating season.
#9. American Bison
- Bison bison
- Adults stand up to 6 feet tall, and males can weigh more than 1 ton while females reach 900 pounds.
- They have long, deep brown fur, cloven hooves, and a noticeable hump over their shoulders.
- Both males and females have short, curved, hollow horns that can grow up to 2 feet.
While you may have heard them called buffalo, the correct name for this species is American Bison. Buffalo are native to Africa and Asia, while Bison, a distantly related animal, is native to North America.
Bison are well adapted to the changing seasons across their range. They’re constantly on the move, walking even while eating. To forage during the winter, they use their large heads to sweep aside the snow. During summer, Bison often wallow, rolling on the ground and creating shallow depressions in the soil. Wallowing helps them to cool off and soothe insect bites.
American Bison were once the most widespread herbivore on the continent, with a population of at least 30 million.
Sadly, by 1900 as few as 1,000 bison remained. While some Bison were hunted for food, most were killed for sport and to drive out Native American groups that relied on Bison as settlers expanded westward. Finally, in the 1900s, they received federal wildlife protection and were brought back from the brink of extinction. Today, approximately 31,000 wild bison are found on federally protected lands and reserves.
- Ovibos moschatus
- Mature bulls (males) are about 5 feet tall at the shoulder, while mature cows (females) stand about 4 feet high.
- They have a dark brown coat of long, coarse outer hair and a fine undercoat.
- Both sexes have horns, but the bulls are much larger and heavier, with bases covering their entire forehead.
Muskox survive in their incredibly harsh arctic habitat by feeding heavily during the summer. They only have a three- or four-month window where vegetation is plentiful. Then, they endure a cold winter with heavy winds, little precipitation, and almost nothing to eat.
Despite their tough nature, these hardy animals are a social species. During the summer, they tend to live in smaller groups with as few as five individuals. However, they form a larger herd of up to sixty Muskox during the winter. These herds help protect individuals from the elements and predators and allow younger animals to graze on vegetation uncovered by older individuals.
Since Muskox are not very fast and can’t outrun predators, they typically will form a circle with their heads facing out when under attack. Then, the calves will hide in the center of the circle for protection. The adults will maintain this formation as they hook or headbutt predators with their horns!
Overhunting drove this impressive mammal in Alaska close to extinction.
Thankfully, Muskox were successfully reintroduced from populations in Eastern Greenland. Today, they are listed as a species of least concern on the IUCN Red List of Endangered Species and are considered stable. However, their relatively small, isolated populations may make them susceptible to pressure from climate change.
#11. Canada Lynx
- Lynx canadensis
- Adults measure 19 to 22 inches tall at the shoulder and weigh between 11 and 37 pounds.
- Their coloring is grayish-brown mixed with buff or pale-brown fur on the back and grayish-white or buff-white fur on the belly, legs, and feet.
- They have long legs, wide, flat paws, long black tufts on triangular ears, and a short black-tipped tail.
Canada Lynx live in cold, moist, boreal forests with snowy winters. The Lynx’s long legs and large paws allow it to hunt and travel in deep snow. This species is exclusively found in areas also occupied by its favorite prey, the Snowshoe Hare.
Lynx are primarily nocturnal and can spot prey up to 250 feet away in the dark. As a result, they are incredibly elusive and rarely seen by humans. A single Canada Lynx may cover more than five miles per day searching for food. They’re excellent swimmers and are adept at climbing trees to escape predators.
Canada Lynx have an interesting, often studied predator-prey relationship with snowshoe hares. The two species are so linked that their populations fluctuate in sync with one another. Adults may survive periods of hare scarcity by hunting other prey. However, Lynx kittens often don’t fare as well during these periods, which leads to a population decrease. When Lynx populations go down, the populations of snowshoe hares rebound, and the cycle starts over again.
#12. Red Fox
- Vulpes vulpes
- Adults range from 18 to 35 inches in length and weigh 7 to 31 pounds.
- Their coloring ranges from pale orange or red to deep reddish-brown on their upper parts with white on their underside.
- They have black feet, a fluffy white-tipped tail, and large, pointy, black-tipped ears.
Red Foxes are arguably the most beautiful mammal in Alaska!
These canines are often thought of as cunning and smart, with good reason! They’re excellent hunters and foragers. They also cache food and are adept at relocating it. Although they prefer rabbits, fish, and berries, they won’t hesitate to eat anything readily available.
This species has a distinctive way of hunting mice and other small rodents. Once the prey has been detected, they stand motionless, waiting and listening. Then they leap high into the air and bring their forelegs straight down, pinning the rodent.
Once baby foxes, known as kits, reach adulthood, their biggest threat is humans, who hunt and trap them for fur or kill them to protect livestock, such as chickens. Red Foxes can live 10 to 12 years in captivity but average only about three years in the wild.
#13. Arctic Fox
- Vulpes lagopus
- Adults average about 43 inches in length, including their tails.
- White phase foxes change from white to brown in the summer.
- Blue phase foxes remain a charcoal color year round but are somewhat lighter in summer.
- Their short legs, ears, and thick coat give them a stocky appearance.
Arctic Foxes prefer treeless tundra in Alaska near rocky shores. But, during the winter, they typically venture out onto the ice pack in search of food.
Their diet often varies with the season. In summer, they feed primarily on small mammals like lemmings and moles. While food is abundant, they will create a cache in their den for later use.
During the winter, they feed on marine animals, invertebrates, sea birds, fish, and seals. They may also eat carrion left behind by polar bears.
It’s uncommon to see groups of Arctic Foxes in the winter because they’re solitary. However, they live in small groups during the summer months. The typical family usually consists of one male, a litter of young, and two females (vixens). One vixen is the male’s mate, and the other is a non-breeding female that helps to care for the pups until the pack disbands for winter.
- Canis latrans
- Adults range in length from 3 to 4.5 feet and weigh between 15 and 44 pounds.
- Their coloring is grayish to yellow-brown on top with white underparts.
- They have a bushy tail, large, triangular ears, narrow muzzle, black nose, and yellow eyes.
Coyotes have a large range in North America and are found in various habitats, from the tropics to the tundra. Coyotes expanded their range after the near extermination of wolves and cougars by European settlers.
As with habitat, coyotes are highly versatile in their food selection. Despite being primarily carnivorous, they consume various plants, including berries, grass, and food crops. They will eat almost anything, and this extensive menu allows them to thrive in nearly every environment in Alaska!
Even if you haven’t seen one, you’ve probably heard a Coyote before! They’re extremely vocal and communicate through howls, yips, whines, and barks. These vocalizations are used to warn pack mates of danger, greet each other, and play.
Sadly, Coyotes are commonly hunted and trapped for fur and sport.
#15. Gray Wolf
- Canis lupus
- Adults range from 3 to 5 feet long and weigh 60 to 145 pounds.
- Their coloring varies from solid white to black but is often a mix of gray and brown with light facial markings and undersides.
- They have long, bushy tails often tipped in black.
Gray Wolves are the largest living canine species! They thrive in various habitats, from tundra to woodlands, forests, grasslands, and deserts.
Within a pack, wolves communicate through body language, barking, growling, howling, and scent marking. Howling may be used for long-distance communication, to call a pack back together, or to warn intruding wolves away. The alpha male and female are typically the only ones who mate, and they do so for life.
Gray Wolves were once a widespread mammal in Alaska, but they were heavily hunted.
Several “extermination campaigns” were held, the earliest recorded in 1630, where officials gave cash rewards to anyone who killed a wolf. By 1970, only 768 wolves were remaining in the US.
Today, Gray Wolves remain extinct in most of their former range. Fortunately, endangered species protection and reintroduction efforts have been successful, most famously with the reintroduction of wolves to Yellowstone National Park.
Apex predators, like wolves, are incredibly important to ecosystems. Without them, there is an overabundance of large herbivores, which typically devastates native vegetation, and increases erosion, among other things.
#16. Snow Shoe Hare
- Lepus americanus
- Adults range from 16.4 to 20.4 inches in length.
- In summer, the fur is a rusty grayish brown with a dark line down the middle of the back.
- In winter, the fur is almost entirely white except for black eyelids and blackened tips of the ears.
Snowshoe Hares are perfectly adapted to cold, snowy areas of boreal and coniferous forests. They get their name from the thick fur and large toes on their back feet, which allow them to run across the snow without sinking in. In warmer climates, Snowshoe Hares are found only in the mountains where the weather is cooler and snowy.
You’re most likely to spot this mammal in Alaska at dawn or after dusk. Snowshoe Hares are primarily herbivorous and consume various plants depending on the season. In summer, they feed on grasses and wildflowers. Then, they switch to buds, twigs, and bark from conifer trees in winter.
About 85% of leverets (baby hares) won’t make it through their first year of life. Those that do survive live up to five years in the wild. They have many predators, including squirrels who eat the young, Lynx, bobcats, mink, wolves, coyotes, and foxes. Unlike rabbits that freeze when threatened, Snowshoe Hares often rely on their speed to escape to cover.
Snowshoe Hare populations are believed to be currently stable. However, researchers believe they face a unique threat from climate change. Regardless if there is snow or not, they continue to turn white in the winter, putting them at an increased risk for predation if they are not blending into their surroundings.
#17. Groundhog (Woodchuck)
- Marmota monax
- Adults measure between 16.3 and 26.6 inches long.
- Their coloring ranges from gray to cinnamon to dark brown, and they have white-tipped guard hairs, which give them a silvery appearance.
- They are stocky, with rounded ears and a bushy tail.
Groundhogs, also called Woodchucks or whistle pigs, occupy forests, fields, pastures, and hedgerows. They thrive near humans, and agriculture operations have increased their food access. Groundhogs construct dens; most have a summer den near food sources and a winter den near protective cover.
In the fall, Groundhogs store large amounts of fat for hibernation. They are “true hibernators,” meaning that their body goes dormant for the entire season. During this time, their heart rate and body temperature fall dramatically until they leave hibernation in late winter or early spring.
Unfortunately, these mammals can become a nuisance in Alaska to farmers, gardeners, and homeowners due to their tunneling behavior. Groundhogs are most affected by vehicle collisions, hunting, trapping, and predation from various species, including domestic dogs.
#18. River Otter
- Lontra canadensis
- Adults grow 3 to 4 feet in length, including their tails.
- Their thick, protective fur is dark brown on the body and lighter brown on the belly and face.
- They have short legs with webbed feet, a long narrow body, and a long, muscular tail.
North American River Otters are semi-aquatic mammals that have an extensive range. They’re found in lakes, rivers, marshes, and estuaries in cold and warm climates. River Otters create dens along the shore that have entrances underwater. They forage at night but can be seen at all times of the day.
River Otters are lively, playful animals and are sometimes even spotted sliding around in the mud or snow. These activities help them to form social bonds and practice hunting techniques.
They use their long whiskers to detect prey in dark water, often grabbing a meal before the victim knows what’s happening. River otters are excellent swimmers, divers, and quick runners. They can stay underwater for up to eight minutes and run 18 miles per hour.
During the 19th and 20th centuries, river otters were heavily trapped and hunted for their fur to near extinction. Conservation and reintroduction efforts are helping many populations to recover; however, some northern populations are still considered vulnerable or imperiled. River Otters continue to face threats from water pollution and habitat destruction.
#19. American Red Squirrel
- Tamiasciurus hudsonicus
- Adults are 11- 14 inches (28 – 35.5 cm) long.
- Their coloring is reddish-brown with a white belly.
- These tiny squirrels have inquisitive-looking faces with bright white rings around their eyes.
The American Red Squirrel is easy to identify compared to other squirrel species. As the name suggests, they have a reddish color and white belly that makes them easy to distinguish. Size-wise, they are both MUCH smaller than both gray and fox squirrels but larger than chipmunks.
American Red Squirrel Range Map
These small mammals are primarily found in southern Alaska in coniferous forests due to their diet, which consists of seeds from evergreen trees. But they are equally at home in deciduous forests, backyards, parks, and urban areas, where they adjust their diet to eat foods such as berries, bird eggs, acorns, hazelnuts, mushrooms, mice, and sunflower seeds from backyard bird feeding stations. American Red Squirrels even have a sweet tooth and are known to tap maple trees so they can eat the sugar from the sap!
These squirrels are BEST known for their aggressive personality!
Press PLAY to hear the sounds of an American Red Squirrel!
When I go hiking, I almost always see at least one American Red Squirrel, as they are not shy creatures. As soon as I’m spotted, the squirrel typically runs up a tree to sit and starts making loud chattering noises to alert the whole forest to my presence!
#20. Brown Rat
- Rattus norvegicus
Look for Brown Rats anywhere people are living, particularly in urban environments. They’re best known for living in sewer tunnels and subway systems, scavenging food from the trash.
Believe it or not, this small mammal isn’t native to Alaska. It’s thought to have originated in China and Mongolia.
Although many people find rats off-putting, others keep a sub-species of Brown Rats as pets. This subspecies, called the Fancy Rat, was bred specifically for the pet trade. Besides companion animals, rats can be trained for many jobs to assist humans, like detecting gunpowder for forensic teams and providing therapy support.
It’s a misconception that Brown Rats spread bubonic plague. In actuality, it’s more commonly spread through ground squirrels! Regardless, they can transmit infections of many kinds, as their blood can carry several diseases.
#21. Black Rat
- Rattus rattus
Interestingly, this small mammal is not native to Alaska.
Instead, it’s thought that the Black Rat came from India and was transported to North America on cargo ships. It’s now so widespread that it’s no longer considered a foreign species.
It’s considered a pest in the agricultural market because it feeds on various crops. Like other rodents, Black Rats can carry pathogens in their bodies. While they may not appear sick, they can spread infections like toxoplasmosis, typhus, and bubonic plague.
In many areas where the Black Rat was once the dominant species, the Brown Rat has taken over. Black Rats are slightly smaller and reproduce less often, two of the reasons this species isn’t as widespread as Brown Rats.
#22. House Mouse
- Mus musculus
Few mammals in Alaska thrive around people as well as the House Mouse!
House Mice have the characteristic large ears, thin tails, and tiny bodies of a typical “mouse.” They do incredibly well in highly populated areas, and there are now more semi-tame populations than wild.
House Mice are the most common species to find inside your home because they’re adaptable to human presence. They readily eat food scraps, build their nests in walls or dark attics and basements, and spend most of their time hidden from view. You’ve likely shared your home with a House Mouse at least once over the years. Although most people would prefer not to have them, they aren’t the worst roommates!
Like their eating habits, they are adaptable in their social behavior. House Mice with an excess of food, like those living in buildings, form a hierarchy with leaders and followers. However, in the wild, where food is less plentiful, females aggressively protect their territory from one another.
#23. American Beaver
- Castor canadensis
- Adults are 29 to 35 inches long, with a tail length between 7.9 and 13.8 inches, and weigh between 24 and 71 pounds.
- They have a dark brown coat of waterproof fur, webbed feet, and a large, flat, black tail.
- Their large, continuously growing incisors (teeth) are orange due to thick layers of enamel.
The American Beaver is North America’s largest rodent!
These incredible mammals are known as ecosystem engineers, meaning they’re one of just a few species that actively work to alter their habitat. They do so by building dams with trees, branches, and mud. Beavers use the dams for shelter, food storage areas, and dens for raising young.
Ponds created by beaver dams serve as important habitats for many types of wildlife. They also help reduce erosion and slow water movement, promoting moisture in drought-prone areas. Especially in northern climates, the water in the pond needs to be deep enough that it doesn’t freeze solid, allowing the beavers to swim under the ice all winter.
Beavers are excellent swimmers and can stay submerged for up to 15 minutes. They spend as much time as possible in the water, where they are less vulnerable to predators. This species uses its large tail to slap the water to signal danger to other beavers, as well as fat storage.
#24. North American Porcupine
- Erethizon dorsatum
- Adults range from 2 to 3 feet in length and weigh about 20 pounds.
- Their fur ranges in color from brownish-yellow to black, with white highlights on their quills.
- Porcupines are covered in approximately 30,000 hollow quills.
While North American Porcupines generally spend much of their time on the ground, they can also climb trees, using their tail for support. But they aren’t the best climbers; one study found that 30% of the porcupines had healed fractures from falling from trees.
They’re well known for their sharp quills used for defense. When threatened, porcupines draw up the skin of their back, bristling so that the quills face all directions. The porcupine keeps its back to the predator and moves its tail back and forth. But, despite their effective defense, porcupines are still preyed on by fisher cats, coyotes, wolverines, and other predators that have adapted to hunting them.
Contrary to popular belief, porcupines can’t throw quills at their attacker! 🙂
#25. American Mink
- Neogale vison
- Adults measure between 12 and 18 inches long, have 6 to 10-inch tails, and weigh between 1 to 3 pounds.
- They have a long sleek body, short stubby legs, long neck, small ears and eyes, slightly webbed feet, and a long thick tail.
- Their fur is brown to black, soft, thick, and covered with oily guard hairs that make it waterproof.
The small mammals can be found in Alaska in forested areas near large water sources. Their dens are located on river banks, under logs and tree stumps, or at the base of trees. Their dens are always close to water.
Minks are voracious predators and feed on surprisingly large prey. Believe it or not, they can eat fish up to 12 inches long and kill coastal birds like seagulls and cormorants by drowning them. Their slightly webbed feet and streamlined bodies are powerful in the water, and they can swim for up to three hours without stopping! While they’re rarely far from water, they hunt on land and can climb trees.
Despite this species being regularly hunted for its fur, its population is stable. However, scientists have expressed concern about the effect of escaped domesticated Minks on wild populations. Released Minks can cause territorial issues with wild populations and may introduce weaker genetics by breeding with wild individuals.
Check out the video of a mink above!
#26. American Ermine
- Mustela richardsonii
- Adults typically range from 6.7 to 13 inches in length. Males are twice as big as females.
- In the summer, their coat is brown on the upper parts and white underneath but turns brilliant white in winter.
- They have slender bodies, small faces, short legs, and oval ears.
American Ermines were originally believed to be a subspecies of the Beringian Ermine or Stoat (Mustela erminea). However, in 2021, a study determined that it was a unique species with distinct genetic features.
These mammals occupy various habitats in Alaska, including forested, herbaceous wetlands, grasslands, and mixed woodlands. Though they prefer to prey on small mammals, they’re quite opportunistic and will also feed on worms, insects, and berries.
Male American Ermines maintain large territories that typically overlap with multiple females. Once fully grown, males disperse to find their own territories, while females remain in their birthplace throughout their lives.
#27. Beringian Ermine (Stoat)
- Mustela erminea
- Adults typically range from 7 to 13 inches in length. Males are twice as big as females.
- In the winter, their short coat is all white; in summer, their underside is yellowish white, and their upper parts are chocolate brown.
- They have a long body, short legs, long neck, triangular head, and slightly protruding round ears.
In the United States, this mammal is ONLY found in Alaska.
Ermines occupy areas adjacent to forests and shrub borders. They are primarily terrestrial but swim and climb well. To identify an Ermine’s nest, look for hollow logs or holes filled with fur and feathers from their prey. Side cavities of their burrows are used for latrines and caching food.
This agile predator hunts both under and above ground. In northern climates, Ermines will hunt under the snow, burrowing quickly toward prey. They often move in a series of leaps and stop to investigate holes and crevices they come across. Sometimes, they stand on their hind legs to survey their surroundings.
#28. American Marten
- Martes americana
- Adults typically range from 12.6 to 17.7 inches in length.
- They have a gray head, a dark brown or black tail, a light brown back, and a cream-colored patch on their chest.
- They are long and slender with long, shiny fur, cat-like ears, large eyes, and sharp, curved claws.
American Martens primarily occupy northern forests with a mixture of mature trees. You might spot them in areas with plenty of downed deadwood and thick vegetation for cover. They are highly adapted to deep snow and are often found in high-elevation forests that experience heavy snowfall.
These mammals are some of the hardest to find in Alaska. They’re solitary, nocturnal, and somewhat arboreal, meaning they spend a great deal of their time in trees and easily move through them.
Despite being excellent climbers and adept swimmers, American Martens primarily hunt on the ground. They typically kill their prey with a bite to the back of their neck. American Martens are sometimes observed chasing their favorite prey species, which are red squirrels.
#29. Least Weasel
- Mustela nivalis
- Adults range from 6 to 9.8 inches in length.
- Their soft, dense fur is brown above and white below; in northern populations, they may molt to all white in the winter.
- They have a long slender body with short legs, prominent whiskers, and black eyes.
While Least Weasels don’t dig their own dens, they occupy abandoned dens from other species. They prefer those at the base of trees or near brush piles, tall grass, or other cover sources.
These mammals are highly specialized predators of small rodents. Species like voles, mice, and lemmings make up their entire diet when they’re abundant. However, Least Weasels are opportunistic and consume carrion, bird eggs, lizards, small fish, and invertebrates. They will forage at all hours of the day and night.
Least Weasels have a very large total population and are common in Eurasia. However, they are a much less common mammal in Alaska and are now thought to require population management in the Southeast. In addition, least Weasels face threats from trapping as well as habitat and prey loss.
- Gulo gulo
- Adults range in length from 25.6 to 41.3 inches.
- They have thick, oily fur that is brown or brownish-black with a silvery facial disk. A yellow or gold stripe runs from the crown of the head laterally across each shoulder and to the rump.
- They are stocky and robust with short, powerful limbs, large heads, sharp, semi-retractable claws, and small rounded ears.
Look for Wolverines exclusively in cold climates. They occupy tundra, alpine forests, and open grasslands at or above the timberline. They need large undisturbed ranges with low human development to thrive.
Incredibly, they can take down prey five times larger than themselves! Their prey includes wild sheep, reindeer, elk, red deer, moose, and roe deer. Wolverines’ large paws allow them to travel through the snow more effectively than larger animals, catching them by surprise.
While attacking, these mammals can reach speeds of almost 30 miles per hour and kill with a bite to the neck. In addition, Wolverines are capable of biting hard enough to break another animal’s bones. Extremely aggressive for their size, Wolverines successfully defend their kills from bears, cougars, and packs of wolves. Pound for pound, many people consider them the toughest animal on the planet.
Which types of mammals have YOU seen in Alaska?
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