Mackenzie Valley Wolf

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Mackenzie valley wolf

Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Family:	Canidae
Genus:	Canis
Species:	C. lupus
Subspecies:	C. l. occidentalis

Trinomial name

Canis lupus occidentalis

Mackenzie Valley wolf range (green)

The Mackenzie Valley Wolf (Canis lupus occidentalis) also known as the Rocky Mountain Wolf, Alaskan Timber Wolf or Canadian Timber Wolf is perhaps the largest subspecies of Gray Wolf in North America. Its range includes parts of the western United States, much of western Canada, and Alaska, including Unimak Island in the Aleutians, and was reintroduced into Yellowstone National Park and central Idaho.^[1]

1 Anatomy
2 Social behaviour
3 Diet
4 Hunting
5 Current status and history
6 References
7 External links
8 Gallery

[edit] Anatomy

A Mackenzie Valley Wolf in Yellowstone.

Mackenzie Valley Wolves typically stand about 32-36 inches (81-91 cm) at the shoulder and males weigh between 100 and 145 pounds (45 - 65 kg). The weight record is held by a wild specimen caught in Alaska in 1939 which weighed 175 pounds.^[2]

The Mackenzie Valley Wolf has a specialized body that has made it one of the world's most efficient hunters. Its thick, long limbs are proportionally built for traversing through rough terrain such as deep snow or the cliffy edges of the Rocky Mountains. Its deep chest hosts large lungs, letting the wolf breathe more efficiently at higher altitudes, and allowing it to exert huge amounts of stamina traveling up to 115km (~70 miles) in one day. Its powerful neck is a very important adaptation: it has to be strong to support the wolf's large head and is crucial for bringing down prey. The Mackenzie Valley Wolf maximizes heat retention through such methods as using its bushy tail to cover its exposed nose during the winter. It sheds its undercoat during the summer months due to the hotter conditions.

The skull is 31cm (12 inches) long and is armed with an impressive array of large canines and carnassial teeth which, when coupled with huge jaw muscles that are evident from the large sagittal crest and wide zygomatic arches, give it an incredible biteforce that is strong enough to break the bones of prey and even crack the femur of moose.

[edit] Social behaviour

In Alaska, pack sizes are generally 6-12 wolves, with some packs as large as 20-30. Territory size averages 600 square miles. Wolf packs in Yellowstone average 9.2 wolves with an average territory of 348 square mile, while wolf packs in Idaho average 11.1 and 364 square mile territories.^[1]

[edit] Diet

The majority of the Mackenzie Valley Wolf's prey includes wood bison, muskox, moose, caribou, deer, and elk. Mackenzie valley wolves introduced into Yellowstone have taken down adult Bison, the largest wild bovid, proving their success and adaptability in a whole new environment.

[edit] Hunting

Success with killing moose has been recorded as low as 10%, this is due to the majority of wolf performed to test out the prey. When preying on large to medium sized animals such as caribou, pack members will in turn chase an ill or disadvantage prey item and wait till they tire. They will then slowly start to tear away at the prey. Prey usually die from disembowellment, shock and exhaustion. For small prey, wolves will bite down and sometimes shake to break the animals back.

[edit] Current status and history

See also:Yellowstone Gray Wolf Reintroduction

A reintroduced gray wolf in Yellowstone National Park

The Mackenzie Valley Wolf was the subspecies used in the Yellowstone reintroduction effort, where it has become a successful apex predator much like it is in its vast northern range. In Yellowstone, it has been crucial in restoring environmental balance in that it has clamped down on the less fit members of the herds on which it feeds, thereby keeping large ungulate numbers in check and allowing certain floral and faunal species to recover, promoting biodiversity. Wolves were also introduced in central Idaho and entered northwest Montana from Canada. The wolf population in the Northern Rockies has since grown to an estimated 1,300 animals.^[3] The wolf population in Alaska is estimated at 7,500-11,000 wolves.

A captive Mackenzie Valley Wolf in the Czech Republic

The protection given to the Mackenzie Valley wolf has allowed it's population to rise drammatically, causing several young animals to leave the boundraries of Yellowstone and establish territories in areas where they may enter conflict with humans. In Wyoming and Idaho, 90 wolves have been killed to date because of livestock run-ins. In Montana, 32 wolves were killed in 2007 by federal agents. The Montana figure does not include an unknown number of wolves killed by ranchers defending their livestock. The death toll hit a record figure of 142 wolves in 2006. Federal officials plan to remove gray wolves in the Northern Rocky Mountains from the endangered species list in February 2008, although court challenges are considered inevitable and could delay a final delisting. In the Rocky mountains, non-lethal responses to livestock kills, such as hazing wolves away from a ranch, are used when they can be pushed into an area without livestock.^[3]

Since it's reintroduction to Yellowstone, the Mackenzie Valley wolf's possible involvement in the decline of elk populations has been a subject of controversy. On one hand, Yellowstone officials have stated that computer analysis indicates that there is greater justification for believing that the human hunting rate and severe climate, account for at least much of the decline, with wolf predation amounting to very little. Others state that the decline is an inevitable result of an exploded wolf population.^[4]