updated July, 2011
Researchers are discovering more about wolves every year. Direct observation of
these complex and intelligent animals in places like the high arctic and Yellowstone,
advances in genetics, and sophisticated tracking devices have unlocked many secrets.
But much about the wolf remains a mystery, and the adage "Never say "Never," and
never say "Always" when the subject is wolves is still true. Full articles and
scientific papers have been written about each of the following questions. We
recommend that you search the Web site for more comprehensive information including
the "Books and Videos About Wolves" section under Basic Wolf Information. At the
end of the FAQ list are three recommendations for obtaining accurate, science-based
facts and information.
How many species of wolves are there in the world?
What are the subspecies (races) of the gray wolf?
Is the red wolf a true wolf or a wolf/coyote hybrid?
What is a wolf pack?
What are the main differences between red wolves and gray wolves?
What is the legal status of the red wolf?
What is a wolf pack?
How many wolves are in a pack?
What is the size of a wolf pack territory?
When do wolves breed?
What is the gestation (pregnancy) period of a wolf?
How many pups are born in a pack each year?
How much do wolf pups weigh?
How much do adult wolves weigh?
How long and tall are wolves?
How big is a wolf's track?
How many teeth does an adult wolf have?
How strong are wolves' jaws?
What do wolves eat?
How much do wolves eat?
How many prey animals do wolves kill per year?
How long do wolves live?
What do wolves die from?
How fast can wolves run?
How far can wolves travel?
Why do wolves howl?
Are wolves dangerous to people?
Will wolves disappear again from the lower 48 states if they are not
federally protected by the Endangered Species Act?
There are two universally recognized species of wolves in the world: the gray wolf
(Canis lupus) and the red wolf (Canis rufus). Two other members of the
canine family are considered to be wolves by some researchers and other species by
other researchers. The use of molecular genetic research on wolves is suggesting that
there may be two more species of wolf in the world. Some scientists question whether
the Ethiopian or Abyssinian wolf (Canis simensis) is a true wolf or a jackal.
Other researchers have presented strong evidence that the eastern timber wolf
(Canis lupus lycaon), may be a distinct species, the eastern wolf (Canis lycaon).
Due to the complex nature of studying wolves using molecular genetics to distinguish
species, the process takes a great amount of time to reach solid conclusions.
The gray wolf, Canis lupus, lives in the northern latitudes around the world.
There are five subspecies, or races, of the gray wolf in North America and seven to
12 in Eurasia. The currently recognized subspecies in North America are:
- Canis lupus baileyi - the Mexican wolf or lobo.
- Canis lupus nubilus - the Great Plains or buffalo wolf.
- Canis lupus occidentalis - the , Rocky Mountain or MacKenzie Valley wolf.
- Canis lupus lycaon - the eastern timber wolf. Some scientists maintain this wolf is a separate species, Canis lycaon.
- Canis lupus arctos- the arctic wolf.
Subspecies are often difficult to distinguish from one another. This is because
wolves are so mobile and travel such great distances. They interbreed where their
ranges overlap so that their populations tend to blend together rather than form
distinctive boundaries. The different traits we see in subspecies are likely the
result of geographic range, available habitat, and prey base. But one wolf is, in
reality, like any other wolf in terms of natural history and behavior. There are
far more commonalities among wolves than differences. All species and subspecies of
wolves are social animals that live and hunt in families called packs, although adult
wolves can and do survive alone. Most wolves hold territories, and all communicate
through body language, vocalization and scent marking.
No single hypothesis for the origin of the red wolf is universally accepted by
scientists. DNA analysis and morphological evidence support recognition of the red
wolf as a distinct species. (See Wolves: Behavior, Ecology, and Conservation -
Red wolves are larger than coyotes and smaller than gray wolves. They are
buff-colored or brown with some black along their backs. The backs of their ears,
head and legs are often tinged with a reddish color. Their legs are long, and they
have tall, offset ears. The red wolf diet consists mainly of white-tailed deer and
small mammals such as marsh rabbits, raccoons and nutria.
The red wolf has federally endangered status throughout its 29-state historic range.
Non-essential experimental status (see Glossary) applies only to the 5-county red
wolf recovery area comprising the Albemarle Peninsula in northeastern North Carolina.
A wolf pack is a cohesive family unit consisting of the adult parents and their
offspring of the current year and perhaps the previous year and sometimes two years
or more. Wolf parents used to be referred to as the alpha male and alpha female or
the alpha pair. These terms have been replaced by "breeding male," "breeding female,"
and "breeding pair" Ð or simply "parents." The adult parents are usually unrelated,
and other unrelated wolves may sometimes join the pack.
Pack size is highly variable and fluid because of the birth of pups, dispersal,
and mortality. Prey availability and size are also factors. Where prey animals are
smaller, packs are often small. Where prey is large, the packs may be larger. For
example, in Alaska and northwestern Canada some packs reportedly have over 20 members.
One pack (Druid Peak pack) in Yellowstone National Park once swelled to over 30 members,
but this is highly unusual and not necessarily an advantage. More pack members means
more food must be obtained. Wolf packs are generally largest in late autumn when the
nearly-grown pups are strong enough to hunt with the adults. Over the winter months,
some wolves may disperse to find mates and territories of their own. Others die, and
by spring, before the arrival of a new crop of pups, the pack size has often diminished.
Red wolf packs are generally smaller than gray wolf packs and usually have 2 to 8
members, but a pack of 12 has been observed in the wild.
In most regions where wolves live, each wolf pack has its own territory, an area
in which it lives, hunts and raises its offspring and which it actively defends against
other canids (dog-like animals) including other wolves. Exceptions are nomadic wolves
whose prey is migratory such as the tundra wolves that follow the caribou herds on
their annual treks over huge distances. Territory size is highly variable and depends
on a number of factors such as prey abundance, the nature of the terrain, climate
and the presence of other predators including other wolf packs. Gray wolf territories
in the lower 48 states may be less than 100 square miles while territories in Alaska
and Canada can range from about 300 to 1,000 square miles or more.
Red wolf territories in northeastern North Carolina vary in size, but most are
estimated to range between 38 to 87 square miles.
Wolves breed once a year in late winter or early spring depending on where they
live. For example, gray wolves in the Western Great Lakes region breed in February
to March, while gray wolves in the arctic may breed a few weeks later - in March to
Red wolves usually breed in late January or early February.
The gestation period (length of pregnancy) of gray and red wolves is usually around
A mature female wolf comes into estrus once a year. Thus, a breeding pair produces
one litter of pups each spring, but in areas of high prey abundance more than one
female in a pack may give birth. An average litter size for gray and red wolves is
4 to 6, but sometimes fewer pups are born and sometimes more. Several or all may die
if food is not readily available for the fast-growing youngsters. Additionally, other
predators and diseases such as distemper and canine parvovirus may kill young pups.
Gray and red wolf pups weigh about a pound at birth. The newborns are blind and deaf
and depend upon their mother for warmth. In about two weeks, their eyes open, and in
three weeks, they emerge from the den and begin to explore their world. Growth is rapid,
and by the time the pups are 6 months old, they are almost as big as the adults.
Wolves vary greatly in size depending on where they live. The smallest wolves live in
the southern parts of the Middle East where the Arabian wolf may weigh no more than 30
pounds. Adult female gray wolves in northern Minnesota weigh between 50 and 85 pounds,
and adult males between 70 and 110 pounds. Gray wolves are larger in the northwestern
United States, Canada, and Alaska and in Russia where adult males weigh 85 to 115 pounds
and occasionally reach 130 pounds. Males generally weigh about 20 percent more than females.
Wolves attain their adult height, length and weight in the first one to two years. Most
look like adults by late autumn of their first year.
Red wolves are intermediate in size and appearance between a gray wolf and a coyote.
Adult female red wolves weigh 40 to 75 pounds, while males weigh from 50 to 85 pounds.
As with weight, a wolf's length and height are variable in different areas of the
world. The figures that follow are commonly used to describe the larger subspecies of
wolves in North America, Europe and central Asia. They are not accurate for several of
the smaller subspecies in the southern latitudes of the Middle East, for example. The
average length (tip of nose to tip of tail) of an adult female gray wolf is 4.5 to 6
feet; adult males average 5 to 6.5 feet. The average height (at the shoulder) of a gray
wolf is 26 to 32 inches.
The average length (tip of nose to tip of tail) of an adult red wolf is 4.5 to 5.5
feet. The average height (at the shoulder) of an adult red wolf is about 26 inches.
The size of a wolf's track is dependent on the age and size of the wolf, as well as
the substrate the track was made in. A good size estimate for a gray wolf's track size
is 4 1/2 inches long by 3 1/2 inches wide. In comparison, a coyote's track will be closer
to 2 1/2 inches long by 1 1/2 inches wide. Only a few breeds of dogs leave tracks longer
than 4 inches (Great Danes, St. Bernards, and some bloodhounds). Red wolves have smaller
feet than gray wolves.
All wolves have feet superbly adapted to long-distance travel over different types of
terrain and through (and over!) snow. The wolf's blocky feet and long, flexible toes
conform to uneven terrain, thus allowing the animal to maintain speed when necessary as
well as a tireless, ground-eating trot when traveling.
Adult gray and red wolves have 42 highly specialized teeth, while adult humans have 32.
The canine teeth, or fangs, can be 2 1/2 inches long and are used for puncturing and
gripping. The incisors are for nipping small pieces of meat; the carnaissial teeth are
like scissors and knives. Wolves use them to sheer flesh away from bones. Molars are for
grinding and crushing.
The massive molars and powerful jaws of a wolf are used to crush the bones of its prey.
The biting capacity of a wolf is 1,000 to 1,500 pounds of pressure per square inch. The
strength of a wolf's jaws makes it possible to bite through a moose femur in six to eight
bites. In comparison, a German shepherd has a biting pressure of 750 pounds per square
inch. A human has a much lower biting pressure of 300 pounds per square inch.
Wolves are carnivores, or meat eaters. Gray wolves prey primarily on ungulates - large,
hoofed mammals such as white-tailed deer, mule deer, moose, elk, caribou, bison, Dall
sheep, musk oxen, and mountain goats. Medium-sized mammals, such as beaver and snowshoe
hares, can be an important secondary food source. Occasionally wolves will prey on birds
or small mammals such as mice and voles, but these are supplementary to their requirements
for large amounts of meat. Wolves have been observed catching fish in places like Alaska
and western Canada. They will also kill and eat domestic livestock such as cattle and sheep,
and they will consume carrion if no fresh meat is available. Some wolves eat small amounts
of fruit, although this is not a significant part of their diet. If prey is abundant,
wolves may not consume an entire carcass, or they may leave entire carcasses without eating.
This is called "surplus killing" and seems inconsistent with the wolves' habit of killing
because they are hungry. Surplus killing seems to occur when prey are vulnerable and easy
to catch - in winter, for instance, when there is deep snow. Since wolves are programmed
to kill when possible, they may simply be taking advantage of unusual situations when wild
prey are relatively easy to catch They may return later to feed on an unconsumed carcass,
or they may leave it to a host of scavengers. Additionally, they may cache food and dig it
up at a later time.
Red wolves primarily prey on white-tailed deer, raccoons, rabbits, nutria and other rodents.
Getting enough to eat is a full-time job for a wolf. When wolves catch and kill a large
mammal, they will gorge and then rest while the food is being rapidly digested. They will
generally consume all but the hide, some of the large bones and skull and the rumen (stomach
contents of ungulates) of their prey. Gray wolves can survive on about 2 1/2 pounds of
food per wolf per day, but they require about 7 pounds per wolf per day to reproduce
successfully. The most a large gray wolf can eat at one time is about 22.5 pounds. Adult
wolves can survive for days and even weeks without food if they have to. Growing pups,
however, require regular nourishment in order to be strong enough to travel and hunt with
the adults by the autumn of their first year. Wolves often rely on food they have cached
after a successful hunt in order to see them through lean times.
Red wolves may eat 2 to 5 pounds of food per day when prey is abundant. Because they
are smaller than gray wolves, they can consume less at one time than their larger cousins.
But like all wolves, eating for red wolves is a matter of "feast" followed by "famine."
Wolves depend on a variety of large ungulates (hoofed animals) for food. Although
studies have been conducted in some areas to determine the actual number of prey killed
each year, the results are estimates. For example, an estimate for deer ranges from 15
to 19 adult-sized deer per wolf per year. Given the 2008 estimate of 2922 wolves in Minnesota,
for instance, that would equal 43,800 to 58,500 deer killed by wolves. In comparison,
hunters killed approximately 260,000 deer in the 2007 deer harvest. Additionally, several
thousand deer are killed during collisions with vehicles each year.
It is misleading to say that wolves in the wild live an average of a certain number
of years. There are so many variables. Some wolves die soon after they are born, and
others are killed or die in early or middle adulthood. Members of the dog family like
wolves and domestic dogs can live to be 15 or 16 years old - sometimes even older. Dogs
and wolves in captivity have a better shot at making it to a ripe old age because they
usually receive routine veterinary care and regular meals. However, wild wolves have a
tough life filled with pitfalls (see question #19). Many pups don't make it through the
first winter of their lives. Those that survive the first two years have a pretty good
chance of living another two to four years if they can avoid fatal injury and if they can
get enough to eat. Some wild wolves do live to be 9 or 10, and there are verified records
of a few living into their early teens.
The natural causes of wolf mortality are primarily starvation, which kills mostly
pups, and death from other wolves because of territory fights. Diseases such as mange,
canine parvovirus and distemper can be killers both in small and recovering populations
and in some established populations as well. Evidence suggests, however, that large wolf
populations build up a resistance to canine parvovirus. Lyme disease also infects wolves,
and heartworm can reduce a wolf's endurance by restricting blood flow to the lungs. Injuries
caused by prey result in some deaths. The large mammals that wolves hunt and kill can
inflict mortal injuries with antlers and hooves. Human-caused mortality including legal
(hunting and trapping in some locales) and illegal (poaching) activities can be high in
some populations. Wolves are sometimes hit by cars in areas where road density is high.
Pup mortality rates are highly variable, but approximately 40 to 60% of wolf pups die
Wolves will travel for long distances by trotting at about five miles per hour. They
can run at speeds of 36 to 38 miles per hour for short bursts while chasing prey. Although
bursts of maximum speed are relatively short, wolves can maintain pursuit of running prey
animals for long distances and over rough terrain.
Wolves are hunters, and they travel far and wide to locate prey. They may travel 50
miles or more each day in search of food, and they are superbly designed for a life on
the move. Because their elbows turn inward, their lean bodies are precisely balanced over
their large feet. With their long legs and ground-eating stride, they can travel tirelessly
for hours on end with no energy wasted. Dispersing wolves, those leaving packs in search
of their own mates, have been known to travel hundreds of miles away from their home
territory. Satellite and Global Positioning Satellite (GPS) collars allow researchers to
document the truly remarkable travels of wolves.
The howl of the wolf is one of nature's most evocative and powerful sounds. The
haunting chorus of wolves howling is beautiful - or frightening depending on one's point
of view. Wolves howl to communicate with one another. They locate members of their own
pack by howling, and they often engage in a group howl before setting off to hunt. The howl
is a clear warning to neighboring wolves to stay away.
In a word, the general answer is no. Wolves typically avoid people. BUT! There are
several well-documented accounts of wild wolves attacking people in North America, and
although there were no witnesses, a 2007 inquest determined that a young man killed in
northern Saskatchewan in 2005 died as a result of a wolf attack. Accounts of wolves killing
people persist in India and in Russia and parts of central Asia. It is a fact that when
wild animals become habituated to people, they may lose their fear of humans, especially
if they are fed or if they associate humans with providing food. Like any large predator,
wolves are perfectly capable of killing people. No one should ever encourage a wolf or
any other wild animal to approach, and hikers and campers should take all necessary
precautions to prevent mishaps involving wildlife.
It is unlikely. The general public is invested in the return and recovery of the great
predators on the landscape. Wolves reproduce rapidly, and every spring brings a new pup
crop to add to the growing numbers in the areas where wolves have made a comeback. Wolves
were eradicated in the 19th and early 20th Centuries by the federal government's systematic
poisoning campaign. It is probably safe to predict that this practice will never be repeated.
Wolves: Behavior, Ecology, and Conservation. L. David Mech and Luigi Boitani.
The University of Chicago Press, 2003.
www.wolf.org. International Wolf Center Web Site.
www.fws.gov/redwolf. Red Wolf Recovery Program Web Site.
www.redwolves.com. Red Wolf Coalition Web Site