of their territory per day, on average . The core of their territory is on average where they spend 50% of their time. Prey density tends to be much higher on the territory's periphery. Except out of desperation, wolves tend to avoid hunting on the fringes of their range to avoid fatal confrontations with neighbouring packs. The smallest territory on record was held by a pack of six wolves in northeastern Minnesota, which occupied an estimated , while the largest was held by an Alaskan pack of ten wolves encompassing . Wolf packs are typically settled, and usually leave their accustomed ranges only during severe food shortages. Territorial fights are among the principal causes of wolf mortality, one study concluding that 14–65% of wolf deaths in Minnesota and the Denali National Park and Preserve were due to other wolves. Communication Wolves communicate using vocalizations, body postures, scent, touch, and taste. The phases of the moon have no effect on wolf vocalization, and despite popular belief, wolves do not howl at the moon. Wolves howl to assemble the pack usually before and after hunts, to pass on an alarm particularly at a den site, to locate each other during a storm, while crossing unfamiliar territory, and to communicate across great distances. Wolf howls can under certain conditions be heard over areas of up to . Other vocalizations include growls, barks and whines. Wolves do not bark as loudly or continuously as dogs do in confrontations, rather barking a few times and then retreating from a perceived danger. Aggressive or self-assertive wolves are characterized by their slow and deliberate movements, high body posture and raised hackles, while submissive ones carry their bodies low, flatten their fur, and lower their ears and tail. Scent marking involves urine, feces, and anal gland scents. This is more effective at advertising territory than howling and is often used in combination with scratch marks. Wolves increase their rate of scent marking when they encounter the marks of wolves from other packs. Lone wolves will rarely mark, but newly bonded pairs will scent mark the most. These marks are generally left every throughout the territory on regular travelways and junctions. Such markers can last for two to three weeks, and are typically placed near rocks, boulders, trees, or the skeletons of large animals. Raised leg urination is considered to be one of the most important forms of scent