Biology and BehaviorCommunicationMany of us think of communication only as talking or writing to each other. Those are two ways humans share information every day. How do wolves "converse?" Even though they cannot talk or write, wolves communicate effectively in several ways.
Wolves use body language to convey the rules of the pack. A wolf pack is very organized. Rule number one says that the pack is made up of leaders and followers. The pack leaders are the male parent and the female parent - usually the father and mother of the other pack members. They are likely to be the oldest, largest, strongest and most intelligent wolves in the pack. They are known as the alpha wolves and are usually the only members of the pack to produce pups.
Any wolf can become an alpha. However, to do so, it must find an unoccupied territory and a member of the opposite sex with which to mate. Or, more rarely, it moves into a pack with a missing alpha and takes its place, or perhaps kills another alpha and usurps its mate.
The alpha male and female are dominant, or in charge of the pack. To communicate dominance, the alphas carry their tails high and stand tall. Less dominant wolves exhibit submissive behavior by holding their tails down and often lower their bodies while pawing at the higher ranking wolves.
There are two levels of submissive behavior: active and passive. Active submission is a contact activity in which signs of inferiority are evident such as crouching, muzzle licking and tail tucking. The behaviors typical of active submission are first used by pups to elicit regurgitation in adults. These behaviors are retained into adulthood by subordinate wolves, where they function as a gesture of intimacy and the acceptance of the differentiation of the roles of the wolves that are involved.
Passive submission is shown when a subordinate wolf lays on its side or back, thus exposing the vulnerable ventral side of its chest and abdomen to the more dominant wolf. The subordinate wolf may also abduct its rear leg to allow for anogenital inspection by the dominant wolf. If two wolves have a disagreement, they may show their teeth and growl at each other. Both wolves try to look as fierce as they can. Usually the less dominant wolf, the subordinate one, gives up before a fight begins. To show that it accepts the other wolf's authority, it rolls over on its back. Reactions to this behavior may range from tolerance (the dominant wolf standing over the submissive wolf) to mortal attack, particularly in the case of a trespassing alien wolf. Following the dominance rules usually keeps the wolves in a pack from fighting among themselves and hurting each other.
Wolves convey much with their bodies. If they are angry, they may stick their ears straight up and bare their teeth. A wolf who is suspicious pulls its ears back and squints. Fear is often shown by flattening the ears against the head. A wolf who wants to play dances and bows playfully.
Wolves have a very good sense of smell about 100 times greater than humans. They use this sense for communication in a variety of ways. Wolves mark their territories with urine and scats, a behavior called scent-marking. When wolves from outside of the pack smell these scents, they know that an area is already occupied. It is likely that pack members can recognize the identity of a packmate by its urine, which is useful when entering a new territory or when packmembers become separated. Dominant animals may scent mark through urination every two minutes. When they do so they raise a leg, this dominant posture utilizes multiple forms of communication and is called a "Raised Leg Urination" or RLU.
Wolves will also use urine to scent mark food caches that have been exhausted. By marking an empty cache, the animal will not waste time digging for food that isn't there.
Wolves use their sense of smell to communicate through chemical messages. These chemical messages between members of the same species are known as "pherimones." Sources of pherimones in wolves include glands on the toes, tail, eyes, anus, genitalia and skin. For example, a male is able to identify a female in estrus by compounds (pherimones) present in her urine and copulation will only be attempted during this time.
Of course, their sense of smell also tells them when food or enemies are near.
Have you ever heard a wolf howl? They're not howling at the moon they are communicating. They call any time of the day, but they are most easily heard in the evening when the wind dies down and wolves are most active. Wolves' vocalizations can be separated into four categories: barking, whimpering, growling, and howling. Sounds created by the wolf may actually be a combination of sounds such as a bark-howl or growl-bark.
Barking is used as a warning. A mother may bark to her pups because she senses danger, or a bark or bark-howl may be used to show aggression in defense of the pack or territory.
Whimpering may be used by a mother to indicate her willingness to nurse her young. It is also used to indicate "I give up" if they are in a submissive position and another wolf is dominating them.
Growling is used as a warning. A wolf may growl at intruding wolves or predators, or to indicate dominance.
Howling is the one form of communication used by wolves that is intended for long distance. A defensive howl is used to keep the pack together and strangers away, to stand their ground and protect young pups who cannot yet travel from danger, and protect kill sites. A social howl is used to locate one another, rally together and possibly just for fun.
Can you think of ways that humans communicate without using words?
How Do Wolves Say Hello?
Have you seen dogs jump up to greet their owners, bark at strangers or roll over when another dog approaches? Then you already know something about how wolves communicate. Dogs inherited most of their language from their ancestors, the wolves.
Wolves use three different languages:
1. Sound - Howls, Barks, Whimpers and Growls.
2. Special Scents - Scats, Urine and Pherimones.
3. Body Language - Body Positions and Movements and Facial Expressions.
Wolf Predation on UngulatesThe wolf is a carnivore, an animal suited for catching, killing and eating other creatures. Wolves prey primarily on large, hoofed mammals called ungulates. In Minnesota, the white-tailed deer is the wolf's primary prey, with moose, beaver, snowshoe hare and other small mammals also being taken. Elsewhere, wolves prey on caribou, musk-oxen, bison, Dall sheep, elk, and mountain goats.
All of these ungulates have adaptations for defense against wolves, including a great sense of smell, good hearing, agility, speed, and sharp hooves. As these prey are so well adapted to protecting themselves, wolves feed upon vulnerable individuals, such as weak, sick, old, or young animals, or healthy animals hindered by deep snow. By killing the inferior animals, wolves help increase the health of their prey population a tiny bit at a time. When inferior animals are removed, the prey population is kept at a lower level and there is more food for the healthy animals to eat. Such "culling" also ensures that the animals which reproduce most often are healthy and well suited for their environment. Over many generations, this selection helps the prey become better adapted for survival.
Wolves require at least 3.7 pounds of meat per day for minimum maintenance. Reproducing and growing wolves may need 2-3 times this much. It has been estimated that wolves consume around 10 pounds of meat per day, on average. However, wolves don't actually eat everyday. Instead, they live a feast or famine lifestyle; they may go several days without a meal and then gorge on over 20 pounds of meat when a kill is made.
In Minnesota, each wolf in eats an average of 15-20 adult-sized deer or their equivalent per year to meet their nutritional requirements,. Based on this average, and the estimate of 3,020 wolves in Minnesota, wolves kill the equivalent of about 45,300 to 60,400 adult-sized deer per year. In comparison, Minnesota hunters take around 52,500 deer per year in wolf range (over 250,000 for the entire state) and several thousand are killed during collisions with vehicles.
Wolf predation on ungulates varies seasonally. It is highest during mid to late winter, when animals are suffering from poor nutrition and the snow is deep, making them easier to kill. It is also quite high in early summer when prey animals have their young, as wolves prey heavily on vulnerable young.
The question of whether wolf predation is additive (the number of animals killed are in addition to those which would die otherwise) or compensatory (animals wolves kill would die anyway) is a complicated one, as wolf predation effects vary with the prey species, time of year, area, and system. It is quite probable that wolf predation is both additive and compensatory, and the real question is how much of it is additive.
For example, wolf predation on deer is moderated by the severity of the winters. In a severe winter, wolves may kill healthy deer which would have survived the winter had they not had been made vulnerable by the deep snow. This would be an example of wolf predation as an additive factor. Conversely, in a mild winter, when the snow levels are low, healthy deer easily escape wolves. Therefore, the deer captured are primarily sick or weak. This would be an example of compensatory mortality, as most of these deer probably would not have survived the winter. This is why it is rare to find a starving deer in Minnesota wolf range.
Reciprocally, prey populations may limit wolf numbers. When considering the examples above, the potential for prey numbers or conditions to regulate wolf numbers is observable. In a mild winter, deer will be healthier and wolves may not be able to catch enough animals to feed themselves. This may cause a decrease in the wolf population. It is also possible that several severe winters in a row would decrease deer populations and wolves may not be able to kill enough food to eat, so again wolf numbers would decrease.
Another factor complicating our ability to determine the precise effect of wolf predation, is that it is difficult to tease out the effects wolves have on their prey populations in areas where there are many different predators. For example, in Yellowstone National Park, in addition to wolves, there are grizzly bears, coyotes, mountain lions, bobcats, lynx, wolverines, and black bears which all prey on Yellowstone ungulates.
In summary, we cannot generalize about what kind of effect wolves have on their prey populations, because their effect is dependent on so many factors. It is possible to get an indication of wolf and prey population trends in a small area or system, but generalizing from one to the other is not always valid.