Spirit Bear Facts | British Columbia Wildlife Guide
Bears are made of the same dust as we, and breathe the same winds and drink of the same waters.
A bear’s days are warmed by the same sun, his dwellings are over domed by the same blue sky, and his life turns and ebbs with heart- pulsings like ours and was poured from the same fountain...”
The Spirit BearThe spirit bear was first formally introduced to the scientific community in 1905 by Dr. William Hornaday of the New York Zoo. Dr. Hornaday considered the spirit bear to be a separate species from the black bear and named it Ursus Kermodei after a Canadian colleague, Francis Kermode. In 1928, however, scientists found that the creamy fur of the Kermode bear is, in actuality, a genetic variation of the MC1R gene in the American black bear.
Theory of OriginMost believe the spirit bear originated from a double-recessive gene—meaning that a white bear is produced when two bears, either black or white, carry the recessive gene that gives the spirit bear its white coat.
Our understanding of the spirit bear is still only in its infancy, as researchers don’t fully understand its occurrence. It is thought that this coastal subspecies evolved over the last 10,000 years, after becoming isolated from inland black bears more than 300,000 years ago. As a result, many of the area’s spirit bears are seemingly gentle towards humans, giving people special insight into these truly wild bears.
Bear BiologyPhysical Characteristics
Like the black bear, the spirit bear is of medium size among bears, with adult males measuring 50 to 75 inches tall and weighing 135 to 600 pounds. Females, which are typically 20 to 60 percent smaller than males, weigh between 90 and 175 pounds. Black bears vary considerably in size depending on the quality of food available.
Adult spirit bears have a completely white coat, which is smooth and short haired. The yellowish hue is speculated to be, in part, related to the ingestion of salmon from streams organically stained with humic acids. These acids may produce or make more pronounced the yellow coloring of the bear in the salmon spawning months. These bears also have long, curved claws, a rounded profile, and no shoulder hump. Smaller than their grizzly bear cousins, the spirit bear is an agile climber, even in adulthood; it uses trees to escape danger or find food.
A bear’s large paws turn slightly inward, and their hind feet have long, somewhat human-like pads. When examining their tracks, the hind foot overlaps the forefoot. Although its gait may appear clumsy, the spirit bear can attain speeds of up to 30 miles-per-hour. They are bright, attentive animals, with an extremely keen sense of smell and exceptional hearing, their eyesight, however, is only average.
Habitat & Population
The spirit bear’s habitat is isolated to the Canadian rain forests of British Columbia, an area about 7.2 million hectares in size. Female home ranges typically encompass one to fifteen square miles. A male’s expansive home range may overlap that of several females, though spirit bears of the same sex will defend their territories from one another. Young female bears are usually allowed to establish their home range within their mother’s territory, while adolescent males must leave.
The spirit bear occupies the area of Gribbell Island and Princess Royal Island along with Pooley Island and the adjacent mainland watersheds. This area is home to approximately one thousand black bears. On Princess Royal Island, approximately 10 percent are thought to be white. While Gribbell Island, the epicenter of the spirit bear gene, 30 percent to 50 percent are white. Sadly, Gribbell Island has no protected status and the remaining spirit bear population is still threatened.
Princess Royal Island and the adjacent mainland are separated by a very narrow waterway—the Graham Reach—which permits the bears to intermingle with island and mainland populations, allowing for genetic diversity. This corridor may be one of the key reasons the white Kermode gene is so apparent in this area.
Aside from the concentration of spirit bears on Princess Royal Island, the area has remained intact despite the deforestation of the surrounding areas, due in part to its isolation. The result is a wilderness haven, comprised of rich fauna, plentiful salmon, and wild bears, which have been sheltered from human interference. The bears, which are partially dependent on old-growth forests, rely on the bounty of Princess Royal Island’s rainforest for both winter denning and vegetation. Salmon, which make up about 95 percent of the spirit bear’s fall diet, are also abundant.
The current population of spirit bears is only approximate. These elusive creatures have always had small numbers, white ones occurring, as the legend states, in one out of every ten black bears on Princess Royal and Gribbell Islands. Elsewhere, however, in the known habitat of the white Kermode, the gene appears in one out of 40 black bears in Terrace and one out of 100 in the Hazelton area.
It is believed that only 400 spirit bears exist in the world. If habitat disruption is a factor in the bears dwindling numbers, then it is very possible that the spirit bear’s survival is dependant on an isolated swath of land, just across the strait from the Queen Charlotte Islands.
Spirit bears are solitary animals that wander all their lives in search of food. Their diet is similar to that of the grizzly bear’s—omnivores who will eat almost anything—but it is more markedly herbivorous. A spirit bear will feast until it can eat no more, hibernate, and begin the process over again.
Depending on the season and the environment, plants make up between 80 and 95 percent of its diet. Bears that feed on a protein-rich food source, however, show significant weight gains and enhanced fecundity. Spirit bears rely on the bounties of the rainforest, eating verdant plants, gleaming berries, and leaping salmon. The bears on Princess Royal Island live on huckleberries, skunk cabbage, and other plants until the protein-packed salmon begin to fill the streams.
When bears emerge from their dens in the springtime, protein-rich food is relatively scarce. Spirit bears will often lose weight at this time, subsisting in part off stored body fat from the previous autumn. As summer arrives, berry-laden bushes appear, along with a bounty of diverse, succulent foods. This abundance of food allows the bears to recover from the harsh winter and spring, and replenish their energy. The bears accumulate great reserves of fat, particularly from the plentiful salmon that return to spawn each year. Building up fat stores during autumn is essential for the winter to come, and mothers especially need the nutrition for suckling cubs.
This unique bear may be seen at any time, day or night, though they are primarily nocturnal. Spirit bears are generally solitary animals, with the exception of mothers with their young. Spirit bears also come together during the mating season, males and females spending several days with each other, and in times of plentiful food, feeding at berry and salmon sites in the summer and autumn.
Bears, with their stunted tails and long hair, are unable to use body language to communicate. This could be why bears frequently use their mouth, head, and neck to express themselves. The position of a bear’s head is important in conveying their mood—lowering their head below the shoulders indicates aggression. In this agitated state, bears will frequently snarl, show their teeth, salivate, open their mouth wide and shut, and make a chomping sound to intimidate their rival.
Throughout the world, bears know to avoid humans by instinct. Generally, a bear will walk away from a person, unless it feels threatened. A mother protecting cubs or a hungry bear pursuing prey may react defensively to an approaching hiker, but most seem to avoid people. The black bear population on Princess Royal Island, however, is different. Here, aside from the Tsimshiam, who once inhabited a coastal village. The bears have been undisturbed for thousands of years, and have no instinctive fear of people. In fact, the Kermode has been observed as a gentle and non-aggressive bear that is thought to only attack a human if its cubs were in danger, or if it was literally starving to death.
Secrets of Hibernation
The spirit bear hibernates between five and seven months each year, subsisting on its stored body fat. The bear prepares for winter in the summer, gorging on a rich diet of wild-grown berries and salmon. During this time, they gain as much as 30 pounds a week. In early fall, a bear and its cubs will make a nest out of raked leaves, twigs, and other plants. Throughout autumn, a bear will become less and less active, until it enters its den for a deep sleep. During wintertime, spirit bears prefer to den in small caves, crevices, and under fallen trees.
The size of the overwintering den is extremely small measuring between 2.5 to five feet in length and two to three feet in height, just barely big enough for a bear to squeeze into. Bears keep warm using their great bulk, as the dens themselves are not very insulating. A spirit bear’s thick layer of fat and dense fur more than doubles in insulative value during the fall in preparation for hibernation.
Once they enter their dens, the bears sleep heavily, refraining from food, water, and bowel movements for up to 100 days. These creatures can continue to slumber due to their toasty fur and ability to retain body heat, maintaining a body temperature of about 88°F (only 12°F lower than their normal temperature). Meanwhile, their metabolism slows down to 25 percent of its normal rate. Spirit bears keep themselves warm enough to awaken if disrupted.
Females reach sexual maturity between two and nine years of age. Males reach sexual maturity at three to four years of age but keep developing until they are ten to twelve years of age, growing until they are able to dominate younger males without a fight. Males do not directly care for their young but will ward off new males, decreasing competition for food and space. Males and females will cohabitate during the breeding season, which lasts from June to mid-July.
Female bears stay in estrus throughout the mating season until they copulate. They generally give birth to cubs every two years, though at times will wait three to four years. After mating in early summer, the fertilized egg begins to divide until it is a spherical sac of one to two millimeters in diameter known as a blastocyst. However, implantation of the embryo into the uterus wall does not yet occur. Instead, the development ceases in a phenomenon called “delayed implantation” or embryonic diapause. The blastocyst finally implants into the wall of the uterus in November, after the female has entered the den and is in hibernation. If the sow was able to build up large fat deposits over the summer, the development of the embryo proceeds to completion, and in late January or early February, the cubs are born in the security of the female’s winter domicile. However, should the bodily reserves of the sow be insufficient to sustain both her and her young until spring, the pregnancy is terminated.
The number of young per litter ranges from one to five cubs, though two or three cubs is most common. Like black bear cubs, spirit bears typically weigh ½ to one pound at birth. They are born blind and remain in the den with their mother throughout the winter. When the family emerges in the spring, the cubs weigh between four and eleven pounds.
A female is quite protective of her cubs, as she teaches them the necessities of survival. Cubs follow their mother’s everywhere, learning from everything she does, including how and where to find food and avoid danger. Cubs take pleasure in wrecking anything that comes into their path, although it appears that they are motivated more by hunger than perversity.
The young are typically weaned after six to eight months but will stay with their mother’s through their second winter, until 17 months of age. Cubs will gradually add solid food to their diet of milk. Around the time a sow’s offspring is no longer reliant on her for sustenance, the mother will drive her cubs out of her home range. They may weigh anywhere from 15 to 100 pounds depending on the abundance of food.
The Future of the Spirit BearThe Looming Threat of Logging
The future survival of the spirit bear is as uncertain as its origins. The enchanting surroundings of the wandering bear are threatened by the imminent danger of logging companies, eager to exploit the timeless rainforests. Though there are many groups vying to save the lands of the spirit bear, forests are rapidly vanishing, risking the survival of this rare subspecies.
Header Credit: Peter Yonemori