Denali National Park & Preserve

Denali National Park & Preserve

Flora & Fauna

Denali National Park and Preserve—one of the country's most remote and unfettered parks—is nonetheless bursting with life! More than 750 species of flowering plants, 39 species of mammals, 166 species of birds, 14 species of fish and even one hardy type of amphibian all thrive within its borders. In fact, a goal of many visitors to Denali is to see the park's "big five"—moose, caribou, Dall sheep, wolf and grizzly bear. If you take a National Park Service concessioner-operated shuttle bus to Wonder Lake or spend time in the backcountry, chances are you will spot one of these species. The majority of visitors report seeing moose, bear, sheep and caribou. Twenty-five percent spot one or more wolves. However, while you search for these dramatic examples of wildlife, don't overlook the park's less imposing, but no less interesting inhabitants. It will surely round out your view of Denali National Park's vibrant natural world.

The Big Five

Outstanding among these animals are the caribou, the Old World domesticated reindeer made famous by the Santa Claus legend! Interestingly, caribou and reindeer are the only members of the deer family in which both male and female have antlers. Though hundreds of caribou graze within Denali National Park and Preserve, their roving disposition makes them relatively elusive. To human observers, the presence of caribou is indicated by the well-defined trails through the tundra, or by battered willows, which the animals have used for rubbing the velvet off their horns.

Vying with the caribou as a wildlife attraction are the groups of white Dall sheep. These are among the most captivating large animals to observe in the park.

The moose, the largest member of the deer family, is also the largest animal found in Denali National Park. Large males, called bulls, often weigh more than 1,000 pounds. Moose in the park tend to live in forested areas that are close to lakes, marshes and other bodies of water. Despite their massive size, they are skillful and graceful swimmers.

Grizzly bears are one of the largest omnivorous animals in North America and are frequently seen within the park. These grizzlies can be seen in close proximity to areas of abundant food, such as berry patches.

There are currently approximately 18 packs of wolves in Denali—comprised of about 100 adult animals. Wolves are noted for their distinctive howl, which they use as a form of communication. Biologists are unsure of all the specific reasons why wolves howl, but they seem to do so before and after a hunt, to sound an alarm and to locate other members of the pack when separated. Wolves howl more frequently in the evening and early morning, especially during winter breeding and pup rearing.


A total of 39 mammals species—ranging in size from the tiny yellow-cheeked vole to the 1,600-pound Alaska bull moose—make their home in Denali Park and all have managed to adapt to survive the brutal winters. During the cold, wintry months of December and January, temperatures can drop to —50°F and a thick layer of snow covers the ground and darkness enshrouds the landscape. Rodents and shrews (who make up more than half the species of mammals in the park) scramble during the summer to store great quantities of food that sustain them through the winter. Red squirrels store spruce cones in piles and burrows on the forest floor. The smallest mammals—mice, voles, shrews and lemmings—depend on food stock- piles while they stay active under a protective layer of winter snow. The largest rodent, the beaver, stores a brush pile at the bottom of its pond; it can be accessed under water from the lodge when the pond is frozen over. Grizzly bears, black bears, hoary marmots and arctic ground squirrels all escape winter food shortages in a comparatively relaxing fashion. They gorge themselves during the fall and spend the winter fast asleep!


While the bears slumber, the park's lone amphibian, the wood frog, spends the cold arctic winter months frozen solid in layers of muck. Wood frogs are just one of many creatures that use "cryoprotectant" chemicals to survive freezing temperatures. As winter approaches, wood frogs prepare for the cold weather by burrowing into decaying leaves on forest floors. As daily temperatures dip below 32°F, the eyeballs and extremities of wood frogs start to freeze. This first sign of freezing stimulates the frog's brain to send a message to the liver—which starts to convert stored glycogen into glucose, a sugar. The glucose circulates through the frog's bloodstream into the cells where it lowers the freezing point of water. The glucose also protects cells from damage and minimizes the effects of dehydration. As the temperature continues to drop, the frogs actually freeze solid. Throughout the entire winter, hibernating frogs are inanimate: they don't breath and their hearts don't beat. Alaskan wood frogs tolerate colder temperatures and freeze for longer periods of time than wood frogs in all other areas of North America, and can survive temperatures as low as —54°F. Scientists have found that core organs, such as the heart and liver, freeze last and thaw first. That means vital body functions such as circulation and metabolism are maintained for the longest possible time. Once the temperatures begin to rise in spring, the frogs thaw—and they're off in search of ponds for breeding.


Denali's avifauna includes a variety of migratory birds that come from all corners of the globe—some from as far away as Siberia, Japan, Hawaii, California, Costa Rica and even Antarctica. Some species, such as the red-throated loon, sandhill crane and long-tailed duck, stop only briefly in the park before continuing to journey north. Others, including the great horned owl, the raven and willow ptarmigan are year-round residents that court, mate, nest, feed and raise their young in the park. The abundance of birds in Denali ebbs and flows with the seasons, increasing significantly as migrants return to the area in the spring and decreasing when they depart on their autumn migration. Summer birding in the park rewards visitors with the opportunity to view these migratory species in a spectacular northern environment. Birding in winter is slim if you calculate by the numbers, but it tends to offer many unusual bird sightings. There are 166 species of birds recorded in Denali National Park and Preserve.


Most fish can't tolerate the rivers inside the park, because these bodies of water contain a milky suspension of pulverized silt—known as rock flour—from glacial runoff. However, freshwater streams and lakes support a number of anadromous and resident fish species. Anadromous fish migrate from salt water to freshwater to spawn, while resident fish remain in Denali's freshwater year-round. At least 14 species of fish are known to occur within the park. They include: chum salmon, chinook salmon, coho salmon, arctic grayling, Dolly Varden, lake trout, northern pike, slimy sculpin, Alaska blackfish, arctic lamprey and longnose sucker.


The vegetation of Denali National Park and Preserve is a mosaic of taiga and tundra ecosystems that is separated into three zones: lowland, sub-alpine and alpine. The lowland zone occurs below 2,500 feet, is predominately forested, and occupies areas underlain by permafrost, mostly north of the Alaska Range crest. Common understory lowland shrubs include alder, dwarf birch, willow and blueberries. Black spruce stands burn regularly; these fires make it uncommon to find trees more than 100 years old. River corridors and upland areas in the lowlands tend to be more productive; these forests include white spruce, paper birch, aspen, rose and cranberry. The subalpine zone, roughly 2,500—4,000 feet in elevation, consists of scrub vegetation dominated by dwarf birch, alder and willow that alternates with open spruce woodland. Other species found in this zone include wormwood, lupine, wintergreen and goldenrod. The alpine zone is generally found above 3,500 feet and consists of tundra, most often dominated by the dwarf species of heath, rose and willow. Due to extensive geomorphic activity and the relatively young age of most surfaces in the alpine zone, many slopes are essentially barren, supporting only a few scattered cushion plants. The upper limit of plant growth is about 7,500 feet; elevations above 8,000 feet are mostly blanketed by glacial ice.

If You See a Bear

Give any bear you see plenty of room. Do not run. Do not make abrupt moves or noises that might startle the animal. If you cannot detour, wait until the bear moves away from your route. Do not try to approach it for a better look or to take a picture. Female bears with cubs or bears defending a carcass are particularly dangerous—so always be alert and respectful.

When Hiking

Make your presence known; do not surprise a bear. Hike in groups and make noise. Many experienced hikers whistle, talk loudly or sing to discourage bears from coming close.

When Camping

Avoid areas that have obvious evidence of bear activity such as digging, tracks or scat. Keep your sleeping gear clean and free of food odor—and sleep at least 100 yards away from your cooking area. Campers must "bearproof" their food: Seal all food and scented items in a bear- resistant food container, which is required in most backcountry units and loaned free of charge with a wilderness permit.