Mexican Gray Wolf

Mexican Gray Wolf

[ Canis lupus ]

Quick Facts


40 to 120 pounds

WILD DIET: about 80% of an adult wolf’s diet comes from whatever hoofed animals live in its habitat (deer, elk, moose, musk ox, bison); the other 20% comes from smaller animals (pheasants, beaver, frogs, rabbits), dead animals, and even some plants
ZOO DIET: dry kibble, beef knucklebones and shank bones
DISTRIBUTION: throughout North America (Hawaii is the only U.S. state where wolves have never lived)
HABITAT: forests, plains, and tundra


In the Company of Wolves

Top dog
Wolves are the largest members of the dog family—which also includes coyotes, foxes, and domestic dogs (though a few breeds of domestic dogs, like the Newfoundland and Saint Bernard, can grow bigger than the largest wolf). All the types of wolves you’ve heard of, like timber, gray, Arctic, and Mexican, belong to the same species: the gray wolf.

All in the family
A wolf pack is an extended family. The alpha male and female rule the pack, which usually includes the current litter of pups and the young adults from a previous litter. Many young wolves leave by age two and form their own pack. Usually only the alpha male and female mate and have pups. The pair actually discourages mating between other pack members. Although wolves often have long lasting attachments to their mates, if one wolf dies the widowed mate may pair up with another wolf.

Who’s in charge here?
The alpha male and female earn their place as pack leaders by being alert, aggressive, and ambitious. They decide when the pack hunts, eats, and sleeps. They mate and often get first choice at feeding time. They may rule the pack for years until others challenge their authority—and win.

Den mother
When the alpha female is pregnant, she looks around for a safe place to have her pups. She looks for an elevated site (so she can scan the area) near fresh water. Once she finds an existing hole, a hollow log, or a large crack between rocks, she enlarges it by digging a birthing tunnel with room enough for her to lie down. The alpha male helps protect the den by acting as a decoy, leading potential predators away from the site.

A pup’s life
Wolf pups are born blind and deaf. At two weeks their eyes open for the first time. At three weeks the pups begin to appear outside the den. They stop drinking their mother’s milk between six to eight weeks and move to a rendezvous site. They also begin to eat solid regurgitated food from the adults of the pack. To encourage adults to regurgitate for them, the pups whine, nudge, nibble, or lick the face and corners of the adults’ mouths. The pups start their learning process by exploring, pouncing on blowing leaves, and play-fighting. This is also the time where they find their place in the social hierarchy of the pack.

Say what?
Wolves are great communicators. They make a variety of howls, yips, squeals, growls, and barks. They have dozens of body postures and facial expressions, which are used as a big part of communication. Howling—something most people associate with wolves—is just one of their a social behaviors, and wolves can hear each other howling from as far as 10 miles away. But howling has absolutely nothing to do with cycles of the moon!

Needed: A few good hunters
To be successful hunters, wolves must be:

  • FIT—Trot 30 miles in one night searching for prey.
  • SMART—Know when to lead, follow, chase, and stop.
  • FAST—Sprint short distances at 40 miles per hour.
  • BOLD—Have the nerve to attack an animal four times their size.
Hunting deer is no picnic! A male deer can crack a wolf’s skull with its antlers. A bison or moose can crack a wolf’s ribs with a single kick. That’s why wolves scan herds for sick, old, or young animals---“safer” prey. Even with all these skills, wolves are not usually successful hunters. Depending on the pack’s size and experience, wolves are successful about 1 in 5 tries for deer, 1 in 18 tries for elk, and 1 in 25 tries for bison.

Brookfield Zoo helps
Mexican gray wolves are a “subspecies,” or subgroup, of gray wolves and would be extinct in the wild if not for the help of zoos and other conservation organizations.

Brookfield Zoo chose to be part of an international recovery program for Mexican gray wolves because they are the most endangered wolves in North America. The Mexican gray wolves living at Brookfield Zoo are part of a multizoo breeding program called a Species Survival Plan (SSP). Because few data about Mexican gray wolves in the wild exist, Brookfield Zoo staff are gathering all of the information they can about the wolves living here. It is possible that offspring from a breeding pair of Brookfield Zoo wolves might one day be a candidate for the release back into the wild. A release is successful when wolves hunt their own food, avoid people, form a healthy pack, and raise pups.

Get Involved

Conservation Fund of the Chicago Zoological Society