BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Canis lupus | Wolf 



TIMING OF MAJOR LIFE HISTORY EVENTS : 
Mating - occurs from January to April
Gestation Period - 63 days
Litter Size - average five to six pups; weaned at 5 weeks
Breeding Age - 2 years, but often do not breed until 3 years due to
               social structure of the pack; usually only dominant
               male and female breed
Life Span - up to 16 years, but 10 years is considered quite old
Pack Size - averages 2 to 15 individuals, although 36 individuals have
            been reported; packs structured in a dominance hierarchy
[10,21,22,35]


PREFERRED HABITAT : 
Gray wolves' habitat preferences appear to be more prey dependent than cover
dependent.  Herman and Willard [16] summarized that gray wolves choose home
territories with a variety of topographic features.  Forests, open
meadows, rocky ridges, and lakes or rivers all comprise a pack's
territory.  In the West gray wolves have been known to follow the seasonal
elevational movements of ungulate herds [16].  In Minnesota, where
territories encompass only subtle elevational changes, Fritts and Mech
[10] observed no changes in territory use by gray wolves between summer and
winter.  In south-central Alaska Ballard and others [1] found that
gray wolves do not follow migrating moose or caribou outside of their pack
territories.  Gray wolves do, however, follow moose and caribous' elevational
movements within pack territories.


COVER REQUIREMENTS : 
Gray wolves excavate natal dens in well-drained soils in meadows near water
[16].  They may use the same den for several years.  In Minnesota Fuller
[11] found gray wolves denning in hollow logs (24 to 35 inches [60-90 cm]
diameter).  Gray wolves also den under tree roots, rock outcrops, or even in
beaver lodges [11].  After 1 to 2 months these natal dens are abandoned
for an open area called a rendez-vous site.  Here the pups are guarded
by a few adult pack members, while the rest of the pack hunts [1].
Herman and Willard [16] summarized that gray wolves need a large, remote area
relatively free from human disturbance.  Territory sizes range from 20
to 215 square miles (54-555 sq km) in Minnesota [10].  Average territory
sizes in Minnesota have been reported to vary from 55 to 120 square
miles (143-310 sq km) [29] and 25 to 29 square miles (64-75 sq km) [2].
In the West average territory sizes vary from 75 to 150 square miles
(194-388 sq km) and are smaller in winter when ungulates are
concentrated on their wintering grounds [16].


FOOD HABITS : 
Gray wolves prey mainly on large ungulates, such as moose (Alces alces), deer
(Odocoileus spp.), elk (Cervus elaphus), and caribou (Rangifer
tarandus).  They tend to prey on the young, old, and sick members of
ungulate populations.  Beaver (Castor canadensis) are a major supplement
to gray wolves' diets [23].  Voigt and others [33] reported that gray wolves'
diets vary, depending on relative prey abundance.  Other prey species
include mountain goats (Oreamnos americanus), bison (Bison bison),
pronghorn (Antilocapra americana), various rodents, upland game birds
and waterfowl, snowshoe hare (Lepus americanus), and black bear (Ursus
americana) [6,10,21,23,25,33]. On Isle Royale seeds of wild sarsaparilla
(Aralia nudicaulis) were found in gray wolf scat [7].  Occasionally gray wolves
prey on domestic livestock.


PREDATORS : 
Humans are the only significant predator of the gray wolf and have eradicated
it from almost all of its former range worldwide [27,34].  Pimlott and
others [26] noted black bear preying on gray wolf cubs and adults.


MANAGEMENT CONSIDERATIONS : 
Organized efforts to kill all the remaining gray wolves in the western United
States began in the 1860's.  Yellowstone and Glacier National Parks
established an official predator-control policy between 1914 and 1926
[27].  Today both parks are included in the Northern Rocky Mountain Wolf
Recovery Plan as two areas capable of sustaining viable wolf
populations.  Bunnell and Kremsater [4] concluded that wolves need about
7,818 square miles (20,250 sq km) to maintain a viable population of 50
individuals.  Fear of livestock depredation seems to be the single most
cause of opposition to gray wolf recovery.  Also hunters worry that game will
be less available if gray wolves were to recolonize their former ranges.  In
Minnesota, northwestern Montana, central Idaho, and the Greater
Yellowstone Ecosystem, livestock owners are reimbursed for animals taken by gray wolves [27].  An economic analysis conducted by Duffield
[36] concluded that gray wolf reintroduction could possibly reduce the number
of hunting permits, but that revenues lost would not exceed revenues
gained from tourism in and around Yellowstone Park, due to the increase
in photographers, filmmakers, and others wanting to see gray wolves.


REFERENCES : 
NO-ENTRY

Related categories for Wildlife Species: Canis lupus | Wolf