Kodiak Island Natural History


Geographic Location and Geologic Setting

Situated in the Gulf of Alaska, Kodiak Island is separated from mainland Alaska by Shelikof Strait. Kodiak Island is located 25 miles (40 km) southeast of the Alaska Peninsula, approximately 90 miles (145 km) southwest of the Kenai Peninsula. The town of Kodiak is 252 air miles (405 km) from Anchorage. Approximately 100 miles (161 km) by 50 miles (80 km), Kodiak is comprised of moderately rugged mountains which average 2,000 to 4,000 feet (610 to 1219 meters) in elevation. The "Emerald Isle" has moderately rocky headlands with glacially sculpted valleys.

Kodiak Island’s geologic activity is characterized by areas of intense activity along the boundaries where tectonic plates collide, and are separated or slide past each other. Earthquakes and volcanoes occur frequently at these plate junctures. In Alaska, the Aleutian Islands and Kodiak are located near a subduction plate boundary approximately 93 miles (150 km) to the southeast. The Pacific Plate is sliding underneath the North American Plate at approximately 2.5 inches or 6 cm per year.


The variety of vegetation and plant communities on Kodiak Island is quite spectacular and provides an unusually attractive array of color, patterns and textures. The mild maritime temperatures and ample rainfall contribute to the abundance of green vegetation that is responsible for Kodiak’s other name, "The Emerald Isle".

Stunningly beautiful coastal wildflower meadows are a highlight for any visitor in summer. Other lowland vegetation includes grasslands, shrub-lands of willows, dwarf birch and alder, rich wetlands and wet tundra. Alpine tundra covers the ridges and grows above tree line, which varies from about 500 to 1,000 feet.

The Sitka spruce forest that adorns the lower elevations, is relatively young, and only covers the northeast end of Kodiak Island, especially in the vicinity of Monashka Bay and Cape Chiniak. It is not mixed with any other species of trees, which makes it unique in the world. It is a forest on the move and is spreading toward the southwest at a rate of about a mile every hundred years. The low protected valleys of central, eastern, and western Kodiak Island contain balsam poplar (cottonwood) and Kenai birch. An abundance of Sitka alder and a variety of willow species grow on the slopes and riparian habitats. The southern two thirds of the island are virtually treeless and support a thick cover of grass and wet tundra.


Kodiak is home to several species of terrestrial mammals ranging in size from the little brown bat to the famous Kodiak brown bear.

The most common species of small mammals are the indigenous brown bat, short-tailed weasel, land otter and tundra vole as well as the introduced red squirrel, beaver, muskrat, house mouse, and the Norway rat.

The Kodiak brown bear is the only large mammal that is native to the island. In the past century, Sitka black-tailed deer, mountain goats, and reindeer have been successfully introduced to Kodiak. Roosevelt elk were successfully transplanted to Afognak Island, where they now constitute a healthy population that occasionally has members that swim across to Kodiak Island.

Kodiak brown bears are a unique subspecies, limited to the Kodiak archipelago. The current population exceeds 3,000 bears that occupy all available habitats on the islands. Recent studies have shown that the Kodiak bear population is healthy and productive. Bear densities are highest in areas that do not have permanent human occupation however, several bears occupy the Kodiak city vicinity. The Kodiak brown bears are arguably the largest in the world and they are an important economic resource for people. Sport hunting is closely regulated by the Alaska Department of Fish and Game, and the U.S. Fish and Wildlife Service provides habitat protection on the Kodiak National Wildlife Refuge.

In the past decade, bear viewing has emerged as an increasingly important human use of the bear population. Bear human interactions are common occurrences in the Kodiak islands and there are few cases where people are seriously injured by bears.

Sitka black-tailed deer are common throughout Kodiak Island, with an estimated population of over 60,000 deer. These ungulates were introduced from southeast Alaska at the turn of the last century and today they provide one of the most important sources of meat to Kodiak residents and many non-local hunters. Deer populations are dramatically impacted by winter and early spring weather conditions, often succumbing to starvation or hypothermia when severe weather persists. In urban areas deer are also vulnerable to loose dogs, especially during the winter and early spring.

Mountain goats were introduced to Kodiak from the Prince William Sound area in the 1950s and now occupy all suitable habitats on Kodiak, with a population of about 2,000 goats. The goats are also an important species to hunters and wildlife viewers. Goat sightings in the mountains near Kodiak city have become more common in the past 10 years as the overall population has been increasing and expanding. There have been no reported adverse encounters between goats and people.

Roosevelt elk were introduced to Afognak Island from the Olympic Peninsula of Washington in the late 1920’s. The population now stands at about 900 elk, occupying most areas on Afognak and Raspberry Islands. Occasionally elk swim across to Kodiak Island but a self-sustaining herd has never been established. There have been unconfirmed sightings of elk in the Monashka Bay area in recent years.

Reindeer were introduced to Kodiak in the 1920’s as an agricultural experiment. By the 1950’s all herding had ceased and the reindeer are now considered feral. About 200 reindeer currently occupy the southwest part of the island and they never venture as far north as the City of Kodiak.

Other domestic livestock that free-range on the island include bison, cattle, and horses. Smaller animals found throughout the area, including the park, include fox, rabbit, muskrat, squirrel and beaver. Harbor seals, sea lions, and sea otter are seen frequently along the coastline.

Weather & Local Climate Information

Kodiak Island has primarily a maritime climate with mild temperature ranges for Alaska. The warm Japanese Current plays a prominent role in producing mild winters and moist, cool summers. Precipitation levels vary widely throughout the year, with June, the driest month, and October the wettest. The average annual temperature is 40.8 °F (4.8 °C). The average annual precipitation is 67.6 inches (171.7 centimeters). Snowfall records average 78.7 inches (199.9 cm) per year (NOAA, 2003). For the majority of the year, the prevailing wind direction is northwesterly. Maximum wind gusts occur during winter months with gusts greater than 58 mph (50 knots).