Kodiak brown bear, Alaskan brown bear
The Kodiak bear (Ursus arctos middendorffi ), also known as the Kodiak brown bear, sometimes the Alaskan brown bear, inhabits the islands of the Kodiak Archipelago in southwest Alaska. It is the largest recognized subspecies or population of the brown bear, and one of the two largest bears alive today, the other being the polar bear.Show More
Physiologically, the Kodiak bear is very similar to the other brown bear subspecies, such as the mainland grizzly bear (Ursus arctos horribilis ) and the extinct California grizzly bear (U. a. californicus ), with the main difference being size. While there is generally much variation in size between brown bears in different areas, most usually weigh between 115 and 360 kg (254 and 794 lb). The Kodiak bear, on the other hand, commonly reaches sizes of 300 to 600 kg (660 to 1,320 lb), and has even been known to exceed a weight of 680 kg (1,500 lb). Despite this large variation in size, the diet and lifestyle of the Kodiak bear do not differ greatly from those of other brown bears.
Kodiak bears have interacted with humans for centuries, especially hunters and other people in the rural coastal regions of the archipelago. The bears are hunted for sport and are encountered by hunters pursuing other species. Less frequently, Kodiak bears are killed by people whose property (such as livestock) or person are threatened. There is increasing focus on conservation and protection of the Kodiak bear population as human activity in its range increases. The IUCN classifies the brown bear (Ursus arctos), of which the Kodiak is a subspecies, as being of "least concern" in terms of endangerment or extinction, though the IUCN does not differentiate between subspecies and thus does not provide a conservation status for the Kodiak population. The Alaska Department of Fish and Game however, along with the United States Fish and Wildlife Service to a lesser extent, closely monitor the size and health of the population and the number of bears hunted in the state.Show Less
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal",...
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A territory is a sociographical area that which an animal consistently defends against the conspecific competition (or, occasionally, against anima...
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Hair colors range from blonde to orange (typically females or bears from southern parts of the archipelago) to dark brown. Cubs often retain a white "natal ring" around their neck for the first few years of life. The Kodiak bear's color is similar to that of its close relatives, the mainland American and Eurasian brown bears.Show More
The size range for females (sows) is from 181 to 318 kg (399 to 701 lb), and for males (boars), it is 272 to 635 kg (600 to 1,400 lb). Mature males average 477–534 kg (1,052–1,177 lb) over the course of the year, and can weigh up to 680 kg (1,500 lb) at peak times. Females are typically about 20% smaller and 30% lighter than males, and adult sizes are attained when they are 6 years old. Bears weigh the least when they emerge from their dens in the spring, and can increase their weight by 20–30% during late summer and fall. Captive bears can sometimes attain weights that are considerably greater than those of their counterparts in the wilderness.
An average adult male measures 244 cm (8 ft 0 in) in length, and stands 133 cm (4 ft 4 in) tall at the shoulder. The largest recorded wild male weighed 751 kg (1,656 lb), and had a hind foot measurement of 46 cm (18 in). A large male Kodiak bear stands up to 1.5 m (4.9 ft) tall at the shoulder, when it is standing on all four legs. When standing fully upright on its hind legs, a large male could reach a height of 3 m (9.8 ft). The largest verified size for a captive Kodiak bear was for a specimen that lived at the Dakota Zoo in Bismarck, North Dakota. Nicknamed "Clyde," he weighed 966 kg (2,130 lb) when he died in June 1987 at the age of 22. According to zoo director Terry Lincoln, Clyde probably weighed close to 1,089 kg (2,400 lb) a year earlier. He still had a fat layer of 9 in (23 cm) when he died. Also, an individual named Teddy, which portrayed a killer bear in the movie Grizzly, stood 3.4 metres (11 ft) tall on hind legs and was the largest bear in captivity at the time.
Kodiak bears are the largest brown bear, comparable in size to polar bears. This makes Kodiak bears and polar bears both the two largest members of the bear family and Kodiak bears the largest extant terrestrial carnivorans.
The standard method of evaluating the size of bears is by measuring their skulls. Most North American hunting organizations and management agencies use calipers to measure the length of the skull (back of sagittal crest on the back of the skull to the front tooth), and the width (maximum width between the zygomatic arches — "cheek bones"). The total skull size is the sum of these two measurements. The largest bear ever killed in North America was from Kodiak Island, with a total skull size of 78.1 cm (30.7 in), and eight of the top 10 brown bears listed in the Boone and Crockett record book are from Kodiak. The average skull size of Kodiak bears that were killed by hunters in the first five years of the 21st century was 63.8 cm (25.1 in) for boars, and 55.4 cm (21.8 in) for sows.Show Less
This brown bear population only occurs on the islands of the Kodiak Archipelago (Kodiak, Afognak, Shuyak, Raspberry, Uganik, Sitkalidak, and adjacent islands). The Kodiak bear population was estimated to include 3,526 bears in 2005, yielding an estimated archipelago-wide population density of 270 bears per 1000 km2 (700 per 1000 sq.mi). During the past decade the population has been slowly increasing.Show More
Bears on Kodiak are naturally active during the day, but when faced with competition for food or space, they adopt a more nocturnal (active at night) lifestyle. This behavior is especially evident in the bears that live near and within Kodiak City. Kodiak bears do not defend territories, but they do have traditional areas that they use each year (home ranges). Because of the rich variety of foods available on Kodiak, the bears on the archipelago have some of the smallest home ranges of any brown bear populations in North America and a great deal of overlap occurs among the ranges of individual bears. Home ranges of adult sows on Kodiak Island average 130 km2 (50 sq mi), while boar home ranges average 250 km2 (97 sq mi).
The islands of the Kodiak Archipelago have a subpolar oceanic climate with cool temperatures, overcast skies, fog, windy conditions and moderate to heavy precipitation throughout most of the year. Although the archipelago only covers about 13,000 km2 (5,000 sq mi), a rich variety of topography and vegetation ranges from dense forests of Sitka spruce on the northern islands, to steep, glaciated mountains rising to Koniag Peak's 1,360 m (4,470 ft) along the central spine of Kodiak Island, to rolling hills and flat tundra on the south end of the archipelago. About 14,000 people live on the archipelago, primarily in and around the city of Kodiak and six outlying villages. Roads and other human alterations are generally limited to Afognak Island and the northeastern part of Kodiak Island. About half of the archipelago is included in the Kodiak National Wildlife Refuge.
Bears live throughout the archipelago, adapting to local resources and retaining relatively small home ranges and comparable densities in most habitats. Emerging vegetation and animals that died during the winter are the first foods bears eat in the spring. As summer progresses, a wide variety of vegetation supplies nutritional needs until salmon return. Salmon runs extend from May through September on most of the archipelago and bears consume the five species of Pacific salmon that spawn in local streams and lakes. In the late summer and early fall, bears consume several types of berries. Bears also feed on wind-rowed seaweed and invertebrates on some beaches throughout the year. Although deer are abundant on the archipelago and mountain goats are abundant on Kodiak Island, few Kodiak bears actively prey on them. Another food source available year-round is the garbage made by the human population of Kodiak Island. As climate change causes elderberries to ripen earlier, berry season is now overlapping with salmon season and some bears are abandoning salmon runs to focus on the berries.Show Less
Kodiak bears begin entering their dens in late October. Pregnant sows are usually the first to go to dens; males are the last. Males begin emerging from their dens in early April, while sows with new cubs may stay in dens until late June. Bears living on the north end of Kodiak Island tend to have longer denning periods than bears in the southern areas. Most Kodiak bears dig their dens in hill or mountain sides and they use a wide variety of denning habitats depending on which part of the archipelago they live. Almost a quarter of the adult bears forgo denning, staying somewhat active throughout the winter.Show More
The Kodiak bear is much like other brown bears in intelligence, although its tendency to feed in large dense groups leads to more complex social behaviors. Kodiak bears are generally solitary in nature; however, when food is concentrated in small areas, such as along salmon spawning streams, grass/sedge flats, berry patches, a dead whale, or even an open garbage dump, they often occur in large groups. Along a few streams on Kodiak, up to 60 bears can be seen simultaneously in a 2.6 km2 (1.0 sq mi) area. To maximize food intake at these ecologically important areas, bears have learned to minimize fighting and fatal interactions by developing a complex communication (both verbal and body posturing) and social structure.Show Less
Kodiak bears reach sexual maturity at age five, but most sows are over nine years old when they successfully wean their first litter. The average time between litters is four years. Sows continue to produce cubs throughout their lives, but their productivity diminishes after they are 20 years old. Mating season for Kodiak bears is during May and June. They are serially monogamous (having one partner at a time), staying together from two days to two weeks. As soon as the egg is fertilized and divides a few times, it enters a state of suspended animation until autumn when it finally implants on the uterine wall and begins to grow again. Cubs are born in the den during January or February. Weighing less than 450 g (1 lb) at birth with little hair and closed eyes, they suckle for several months, emerging from the den in May or June, weighing 6.8–9.1 kilograms (15–20 pounds). Typical litter sizes on Kodiak are two or three cubs, with a long-term average of 2.4 cubs per litter. However, Kodiak bears have six functional nipples and litters up to six cubs have been reported. Sows are sometimes seen with five or six cubs in tow, probably due to adopting cubs from other litters. Most cubs stay with their mothers for three years. Almost half of the cubs die before they leave, with cannibalism by adult males being one of the major causes of death.Show More
Kodiak bears that have recently left their mothers, at ages 3–5 years, have high mortality rates with only 56% of males and 89% of females surviving. Most young female bears stay within or near their mother's home range, while most males move farther away. Most adult sows die of natural causes (56%), while most adult male bears are killed by hunters (91%). The oldest known male bear in the wild was 27 years old, and the oldest female was 35.Show Less
In 1971, the Alaska Native Claims Settlement Act (ANCSA) resolved many long-standing land issues with aboriginal Alaskans statewide. The impacts were felt strongly on the archipelago as large areas were conveyed to the Native corporations. Federal management of the National Forest lands on Afognak was transferred to Native Corporation ownership with passage of the Alaska National Interest Lands Conservation Act in 1980 (ANILCA), and the Kodiak National Wildlife Refuge lost control of 130,000 hectares (310,000 acres) of prime bear habitat (more than 17% of refuge lands).Show More
In 1975, construction of a logging road began on Afognak Island, and timber harvesting began in 1977. In 1979, work began on an environmental impact statement for the Terror Lake hydroelectric project on Kodiak Island. That project included an earthen dam on Terror Lake with Kodiak National Wildlife Refuge and a 10 km (6 mi) tunnel through a mountain ridge to a penstock and powerhouse in the Kizhuyak River drainage. The hydro project was the first significant invasion of inland bear habitat on Kodiak Island. To address the opposition encountered from the public and agencies, a mitigation settlement was negotiated in 1981 which included brown bear research and establishment of the Kodiak Brown Bear Trust. The hydroelectric project was completed in 1985. Human alteration of bear habitat on Kodiak and Afognak Islands spurred renewed interest and funding for bear research on the archipelago, resulting in a surge of baseline and applied bear research on Kodiak through the 1980s and 1990s.
Bears were not directly harmed by the Exxon Valdez oil spill in 1989, although some were displaced from traditional feeding and traveling areas by cleanup crews. No one was injured by a bear, and no Kodiak bears were killed. To mitigate the adverse impacts of the spill, Exxon reached a settlement with the state and federal governments. Paradoxically, the impacts of the oil spill and the subsequent cleanup and settlement proved to be beneficial to bears on Kodiak. Bear-safety training exposed thousands of workers to factual information about bears, and money from the settlement fund was used for funding land acquisitions. By the close of the 20th century, over 80% of the refuge lands that had been lost as a result of ANCSA and ANILCA were reinstated into the refuge, either through direct purchase or by means of conservation easements. Lands were also purchased in America, Westtown, and Shuyak Islands and transferred into state ownership. The Kodiak Brown Bear Trust coordinated a coalition of sportsmen and other wildlife conservation groups from around the nation to lobby for use of settlement funds to acquire Kodiak lands. The groups also directly contributed funding to protect small parcels of important bear habitat around the islands.Show Less
In 2001, a citizens advisory committee was established to work closely with the Alaska Department of Fish and Game (ADF&G), with the cooperation of Kodiak NWR, to develop a management plan addressing several problems that affect bears, including hunting, habitat, and viewing. The resulting Kodiak Archipelago Bear Conservation and Management Plan was crafted over several months by representatives from 12 diverse user groups, which, after hearing from a variety of experts from agencies and receiving extensive public input, developed more than 270 recommendations for managing and conserving Kodiak bears. Despite the diversity of viewpoints expressed by members of the group, all of the recommendations were by consensus.Show More
The underlying themes of the recommendations were continued conservation of the bear population at its current level, increased education programs to teach people how to live with bears on Kodiak, and protection of bear habitat with allowances for continued human use of the archipelago. Although the group's role is merely advisory, government management agencies expressed a commitment to implement all of the regulations that were feasible and within their legal jurisdictions.Show Less