Mexican Gray Wolf

## Description

The Mexican wolf (Canis lupus baileyi ), also known as the lobo, is a subspecies of gray wolf native to southeastern Arizona and southern New Mexico in the United States, and northern Mexico; it also previously ranged into western Texas. It is the smallest of North America's gray wolves, and is similar to the extinct Great Plains wolf (C. l. nubilus ), though it is distinguished by its smaller, narrower skull and its darker pelt, which is yellowish-gray and heavily clouded with black over the back and tail. Its ancestors were likely the first gray wolves to enter North America after the extinction of the Beringian wolf, as indicated by its southern range and basal physical and genetic characteristics.

Though once held in high regard in Pre-Columbian Mexico, it is the most endangered gray wolf subspecies in North America (if counting the red wolf as a separate species), having been extirpated in the wild during the mid-1900s through a combination of hunting, trapping, poisoning and digging pups from dens. After being listed under the Endangered Species Act in 1976, the United States and Mexico collaborated to capture all lobos remaining in the wild. This extreme measure prevented the lobos' extinction. Five wild Mexican wolves (four males and one pregnant female) were captured alive in Mexico from 1977 to 1980 and used to start a captive breeding program. From this program, captive-bred Mexican wolves were released into recovery areas in Arizona and New Mexico beginning in 1998 in order to assist the animals' recolonization of their former historical range.

As of 2021, there are 186 wild Mexican wolves, and 350 in captive breeding programs, a large improvement over the 11 individuals that were released in Arizona in 1998. 2021 was the most successful year to date for the recovery program, resulting in the highest number of individuals, pups born, pups survived, and packs. Approximately 60% of total individuals were found in New Mexico and 40% in Arizona although historically on average both states have had similar amounts of wolves. In 2021, the U.S. population had nearly doubled in the past 5 years. These numbers represent the minimum amount of wolves since survey numbers only include wolf sightings confirmed by Interagency Field Team staff.

## Appearance

A subspecies of the Gray wolf, the Mexican gray wolf is commonly known as "El lobo". It is gray with light brown colored fur on its back, and has long legs and a sleek body, which means it can run fast. Once there were thousands of these wolves but in the U.S. many had been killed by the mid-1970s, and just a handful existed in zoos. In 1998, the U.S. Fish and Wildlife Service, under Jamie Rappaport Clark (who became president of Defenders of Wildlife), introduced 11 Mexican gray wolves into the wild in Arizona. Their numbers have grown slowly and they are currently the world’s most endangered wolf subspecies. These animals can live in captivity for up to 15 years, but it is suggested that their life span is rather less in the wild, probably not more than 10 years.

## Distribution

Mexican gray wolves were once widespread from central Mexico through the southwestern U.S. They have now been reintroduced in southeastern Arizona in the Apache National Forest, and may move into western New Mexico to the adjacent Gila National Forest as the population grows. These wolves are also being reintroduced in Mexico. They prefer habitats of mountain forests, scrublands and grasslands.

## Behavior

Mexican gray wolves are a very social species, living in packs which have complex social structures, including the alpha male and female, the breeding pair, with their offspring. The others in the pack are “helpers”. The hierarchy of dominant and subordinate individuals enables the unit to work. Wolves usually travel with their pack and establish a territory that could be 30 square miles up to more than 500. They define their territory with scent markings and vocalizations such as barks, growls, and their legendary howl. Packs in regions such as the desert where typically prey is small may have 7 or fewer members, up to 30 or more where the prey is large.

## Diet

Mexican gray wolves are carnivores, they eat mule deer, white-tailed deer and elk, and sometimes smaller mammals such as ground squirrels, rabbits and mice.

## Reproduction

Mexican wolves are monogamous, with only the pack’s alpha pair breeding each year. The season for mating is from mid-February to mid-March and gestation lasts about 63 days. Litters number 4 to 7 pups, which are born blind. They are reared inside a den which is a burrow or natural hole. Every member of the pack cares for the pups, feeding them regurgitated meat after hunts. They are weaned in about the fifth week, approaching adult size early in winter. By autumn, when the pups are able to travel with the adults, a pack will hunt throughout its territory as a unit. Juveniles stay with the pack for about two years, when they reach reproductive maturity, and may leave to find a mate and establish a new territory, or remain as a helper.

## Population

### Threats

Humans are the biggest threat to this species. Mexican gray wolves were common about 100 years ago, but then many wolves were killed due to competition for the same resources with humans. In the late 1800's, once railroads were built, large numbers of settlers moved to the southwest. There was no protection at that time for wildlife. Many of the prey animals for this species were killed, and wolves were trapped, poisoned, or shot to protect people's livestock. Many wolves were also killed because fables (such as "Little Red Riding Hood") portray wolves as ferocious killers, or cunning tricksters, which does not reflect the true behavior of wolves.

### Number

According to the U.S. Fish and Wildlife Service, the total population size of the Mexican wolf in 2015 was 97 individuals in the wild. This includes 50 wolves in Arizona, 47 wolves in New Mexico and 7 breeding pairs in total. About 300 wolves in 48 different facilities live in the U.S. and Mexico. Mexican gray wolves are listed as Endangered by the Endangered Species Act (ESA) (NMFS NOAA Fisheries).

## Fun Facts

Mexican gray wolves are the smallest of the Gray wolf subspecies, being around half the size of North American gray wolves.

The Mexican gray wolf is the world’s most endangered wolf.

The fur of Mexican gray wolves is a mixture of gray, black, rust, and cream.

Mexican gray wolves wag their tails, howl, yip, growl, play, and mark their territory with urine.

Mexican gray wolves usually eat only twice a week, and eat as much as 20 pounds of meat in one go.

Wolves do not sleep cuddled up with each other in wolf dens, as many believe. In fact, they sleep in the open, whatever the weather. They establish their sleeping area by circling it before lying down.