Wolves communicate through body language, vocalizations and their sense of smell. Vocalizations often take the form of howling, barking or whimpering, and they are an important part of wolf culture. Wolves primarily convey messages through body language and posturing. One of the important things they communicate is social status. Wolves assert their dominance by barring their teeth, flattening their ears or by carrying a raised tail.
Wolves smell the hindquarters of other wolves to determine their health, reproductive status and similar characteristics. Additionally, wolves use their urine to communicate messages to other wolves. Wolves urinate on trees and rocks in their territory to communicate that the territory is occupied. This helps to dissuade other wolves from trespassing on their territory. Sometimes wolves even seek to communicate with themselves by urinating on exhausted food caches. This prevents them from expending the energy to dig up the cache for no reason, and it is somewhat similar to the way humans may leave themselves a reminder on the refrigerator.
Because wolves are effective communicators, they have been able to evolve very intricate social structures. These social adaptations allow wolves to form packs, which in turn allow them to bring down very large prey.