Grizzly bear - Wikipedia
Relationships between large predators and their prey in Alaska are complex, and no Grizzly bears have been shown to be particularly effective predators of. Predator avoidance • Predator-prey relationships •. Ursus arctos. Introduction brown bear populations depends on habitat quality, human density, and human. Have a “Kodiak” moment with the awe-inspiring brown bear. A Syrian brown bear (Ursus arctos syriacus), a subspecies of brown bear, Diet: Omnivores.
In this regard, one grizzly bear is equivalent to many black bears. Not all bears are equal, however, and some bears seem to become specialists at killing both adult and calf moose.
Black bears have been found to be the most important predator of moose calves in some areas of Alaska where grizzly bears are uncommon. Most predation was by adult males. Biologists expect that significant reductions in bear numbers either black or grizzly or both will also lead to higher numbers of moose for harvest. For example, in areas of Canada and the northern states where moose coexist only with wolves, moose are often found at high densities that fluctuate with weather and habitat e.
Numbers of grizzly bears have probably increased in Interior Alaska since the s.
We base this on incidental observations by older hunters, local residents, cabin owners, and Native elders, who all indicate that grizzly bear numbers have increased. This is corroborated to some degree by modern studies.
For example, grizzly bears were recently found to be significant predators of moose calves on the Yukon Flats and are commonly seen by local residents, whereas years ago, observations of grizzly bears were rare.
In the Anchorage and Fairbanks areas, where wolves and bears are not common, moose are abundant. Grizzly bear populations appear to be much more resilient to harvest than previously believed.
During the last 10 years, the Alaska Board of Game has made a deliberate effort to reduce numbers of grizzly bears in a few important hunting areas e. Game Management Unit the Nelchina Basin by increasing the bag limit and extending hunting seasons. So far, these new regulations have had no noticeable affect on grizzly bear populations even though hunters have taken an increased number of bears.
Wolves have been found to be very adaptable and they recover from low numbers within a few years. Despite relatively heavy hunting and trapping over the last century in Alaska, wolves occur on nearly all of their traditional habitat throughout mainland Alaska. Historically, wolf numbers were greatly depressed. Specifically, wolves were rare in Interior Alaska between about andand during the s. During wolves may have succumbed to diseases brought in by sled dogs or to widespread poisoning.
During the s, federal predator control agents reduced wolves by poisoning and aerial shooting. Wolves have been abundant and have occurred in all of their historic ranges in Alaska since state management began in about except for the Anchorage and Fairbanks areas, and the western Seward Peninsula.
Wolves are social animals that live in large family groups. Usually, only a single female per pack successfully raises pups, but depending upon the relationship of adult males and females in a wolf pack, multiple litters may occur in a single pack in a single year. Most pups born into a pack stay in the pack for at least one year, but virtually all have dispersed away from their natal pack by the age of 3. Large packs of 20 or more wolves may occur in areas where food is abundant and pup survival is high.
High reproductive rates, high mortality rates and long distance dispersal behavior results in extensive gene flow within wolf populations and between wolf packs. In Alaska and other areas, if wolves are not hunted or trapped, most mortality is from intraspecific aggression fighting with other wolves.
In trapped wolf populations, natural mortality rates are often lower than in untrapped populations. In coastal areas of Alaska, where fox rabies is endemic, wolves are periodically reduced to low levels by rabies. LDDE does not present a biological problem — moose are not likely to become threatened, endangered or extinct due to predation. The fact that the LDDE prevails in large areas does not usually present a management problem either.
Dens may be used on repeated occasions over the years.
Brown bear - Wikipedia
Size Brown bears can grow to a huge size, males up to kg, females to kg. The biggest brown bear was caught in Romania and weighed kg. Colour Although the pelage of this species is usually dark brown, it can vary from cream to almost black depending on the location of the species. In the Rocky Mountains USAthey have long hairs on the shoulders and back which are frosted with white.
In Europe, the brown bear is mostly found in mountain woodlands, in Siberia it occurs primarily in forests while in North America they prefer tundra, alpine meadows and coastlines.
Competition between apex predators? Brown bears decrease wolf kill rate on two continents
The species' main requirements are areas with dense cover in which they can shelter by day. Life Cycle Young born bears are vulnerable, being blind, naked and weighing only g. Cubs grow quickly, reaching 25kg by 6 months, and continue lactating for 18 to 30 months while eating a variety of foods. Cubs usually remain with the mother until the third or fourth year of their life.
Although they mature sexually between years of age, the species continues to grow until years old. In the wild, the brown bears can reach 20 to 30 years of age.
Despite this long life expectancy, most brown bears die very early. Breeding Brown bears mate from May to July, and a gestation of to days follows, with births occurring from January to March, usually while the female is still in hibernation.