<P> Wolves are highly territorial animals, and generally establish territories far larger than they require to survive in order to assure a steady supply of prey . Territory size depends largely on the amount of prey available and the age of the pack's pups, tending to increase in size in areas with low prey populations or when the pups reach the age of 6 months, thus having the same nutritional needs as adults . Wolf packs travel constantly in search of prey, covering roughly 9% of their territory per day (average 25 km / d (16 mi / d)). The core of their territory is on average 35 km (14 sq mi), in which they spend 50% of their time . Prey density tends to be much higher in the territory's surrounding areas, though wolves tend to avoid hunting in the fringes of their range unless desperate, because of the possibility of fatal encounters with neighboring packs . The smallest territory on record was held by a pack of six wolves in northeastern Minnesota, which occupied an estimated 33 km (13 sq mi), while the largest was held by an Alaskan pack of ten wolves encompassing a 6,272 km (2,422 sq mi) area . Wolf packs are typically settled, and usually only leave their accustomed ranges during severe food shortages . </P> <P> Wolves defend their territories from other packs through a combination of scent marking, direct attacks and howling (see Communication). Scent marking is used for territorial advertisement, and involves urination, defecation and ground scratching . Scent marks are generally left every 240 m (260 yd) throughout the territory on regular travelways and junctions . Such markers can last for 2--3 weeks, and are typically placed near rocks, boulders, trees, or the skeletons of large animals . Territorial fights are among the principal causes of wolf mortality, with one study concluding that 14--65% of wolf deaths in Minnesota and the Denali National Park and Preserve were due to predation by other wolves . </P> <P> The gray wolf is generally monogamous, with mated pairs usually remaining together for life . Upon the death of one mated wolf, pairs are quickly re-established . Since males often predominate in any given wolf population, unpaired females are a rarity . If a dispersing male gray wolf is unable to establish a territory or find a mate, he mates with the daughters of already established breeding pairs from other packs . Such gray wolves are termed "Casanova wolves" and, unlike males from established packs, they do not form pair bonds with the females they mate with . Some gray wolf packs may have multiple breeding females this way, as is the case in Yellowstone National Park . Gray wolves also practice alloparental care, in which a wolf pair may adopt the pup or pups of another . This might take place if the original parents die or are for some reason separated from them . In addition to heterosexual behavior, homosexual behavior has been observed in gray wolves . Male gray wolves often mount each other when the highest ranking female in the pack comes into heat . </P> <P> The age of first breeding in gray wolves depends largely on environmental factors: when food is plentiful, or when wolf populations are heavily managed, wolves can rear pups at younger ages in order to better exploit abundant resources . This is further demonstrated by the fact that captive wolves have been known to breed as soon as they reach 9--10 months, while the youngest recorded breeding wolves in the wild were 2 years old . Females are capable of producing pups every year, with one litter annually being the average . Unlike the coyote, the gray wolf never reaches reproductive senescence . Estrus typically occurs in late winter, with older, multiparous females entering estrus 2--3 weeks earlier than younger females . During pregnancy, female wolves remain in a den located away from the peripheral zone of their territories, where violent encounters with other packs are more likely . Old females usually whelp in the den of their previous litter, while younger females typically den near their birthplace . The gestation period lasts 62--75 days, with pups usually being born in the summer period . </P>

What are the characteristics of a grey wolf