Mexican Grey Wolf || Abigail Gnewuch

Canis lupus baileyi

The Mexican Grey Wolf

Description and Ecology of Organism

The Mexican Wolf is an endangered species, and is a subspecies of the Grey Wolf. These wolves are primarily grey, with tufts of light brown fur on their back; yet there are many with a more diverse arrangement of colors. They are quick and agile predators and fast runners, which they owe to their sleek body and long legs. The wolf normally reaches a weight of 60-80 pounds, a height of 26-32 inches, and a length of 4.5-5.5 feet. The males tend to be the larger sex. The life span of a typical Mexican Wolf is 15 years. 

Their mating season occurs in the Winter from mid February to mid March, and they have a gestation period of approximately 63 days. A typical litter will produce 4-7 pups. These pups are born blind and defenseless, and are therefore highly dependent on their mothers. The pack will care for the pups for around 10 months, until they have matured.

The Mexican Wolf originally had a large of habitat ranging from the southwestern United States throughout central Mexico. They thrive in habitats consisting of forests, scrublands, and grasslands. 

The Mexican Wolf is a top predator and lives in packs; they require a large amount of forested land, and a sufficient ungulate population to support them. The Mexican Wolf primarily preys on ungulates, which are large hoofed animals, and which include elk and deer. They are also known to prey on smaller mammals such as rabbits, squirrels, mice, and javelinas.

Geographic and Population Changes

As stated above, the Mexican Wolf originally had a large range of habitat, from central Mexico to the southwestern United States. Eventually, they were completely wiped out of the United States and only a small number remained in Mexico. With only a few wolves remaining, a recovery plan came about and the wolves started being bred in captivity and then, beginning in 1998, were reintroduced into the wild in Arizona. This effort was ongoing and continued for several years. As of 2016, all Mexican wolves in the States were either wild-born or cross-fostered pups from captivity. 

In Mexico, they have also been reintroducing wolves into the wild since 2011, and this process is still in the early phases today. In the first five years of this project, forty-one wolves were released. They will continue this process until there is a large enough population in the wild to support their own sustainable and growing population.

"We conducted fourteen releases of wolves from captivity including 10 cross-fostered pups, between 2009 and 2017, during which time the population are from a minimum population count of 42 to 113 wolves. We have documented wild-born wolves breeding and raising pups in the wild for 16 consecutive years" (Wolf Recovery Plan pg. 7). 

We can see that not only is the population rising, but so is the reproduction rates, and the number of living pups. 

Listing Date and Type of Listing

Canis lupus baileyi has been classified as an endangered species since 1976 under the Endangered Species Act of 1973. The species was saved from extinction when a binational captive breeding population was put into place, which came down from seven Mexican Wolf founders. 

Cause of listing and Main threats to its continued existence

The threatened extinction of the Mexican Wolf was due to illegal shooting, genetic problems, and small population size. The genetic problems included inbreeding, decline in adaptive potential, and and loss of heterozygosity. 

There are four threats to its continued existence, according to the recovery plan (page 9), and they are listed as follows:

1) adequate habitat availability/suitability

2) excessive human-caused mortality

3) demographic stochasticity associated with small population size

4) continuing or accelerated loss of genetic diversity in the captive or wild populations

Description of Recovery Plan

The purpose of the recovery plan is ensure the long time survival of the Mexican Wolf, which is accomplished by protecting and conserving the species, as well as its habitat. Once the species is well established and can withstand continuing threats, it will be removed from the endangered and threatened species list! There are several objectives to the recovery plan for the Mexican Wolf, which are listed on page 18 of the recovery plan.

1. Increase the size of two Mexican wolf populations

2. Improve gene diversity and maintain the health of Mexican wolves

3. Ensure adequate habitat availability to support viable Mexican wolf populations

4. Maintain the Mexican Wolf Species Survival Plan (SSP) captive breeding program to improve the status of wild populations

5. Promote Mexican wolf conservation through education and outreach programs

6. Ensure recovery success. 

There are two options regarding the criteria for delisting the Mexican Wolf from the endangered species list. The first involves a population in the United States over a 4-year period being equal to or larger than 320 wolves; there also must be adequate genetic diversity among the species. The second option requires that at least two populations, one in the States and one in Mexico, over a four year period are able to each reach a population that is equal to or large than 150 wolves; these also must have a positive growth rate in their population. 

What can you do?

This plan is already taking effect, and is thriving! A lot of the support it needed in order to get the ball rolling has already been achieved. So what else can be done?

Recovery of this species is predicted in 25-35 years, and the project is costing approximately  $178,439,000. If you want to donate to this effort, or to other species recovery efforts that are taking place across the world, that is always a huge help!

Informing others about what you know is also always a great way to help! The more informed people there are regarding these important issues, the more people there are who will get behind the efforts, and then an even greater difference can be made.

A problem that originally threatened this species is that they were being illegaly hunted. If you are a hunter, make sure you have a permit, and you are not hunting any endangered or protected species! 

If you happen to travel to this area where the Mexican Grey Wolf dwells, make sure not to disrupt or damage their habitat. Habitat suitability and availability is a huge factor to their survival!

Other resources

This video provides some great information on the story of the Mexican Grey Wolf! (https://www.youtube.com/watch?v=OeqzdZt10XA)

This is a really awesome video showing wildlife managers capturing, counting, monitoring, collaring, and releasing the Mexican Grey Wolf. (https://www.youtube.com/watch?v=IfMg24z1lsY)

Sources

“BASIC FACTS ABOUT MEXICAN GRAY WOLVES.” Defenders of Wildlife, defenders.org/mexican-gray-wolf/basic-facts.

“Mexican Wolf Recovery Plan - First Revision.” US Fish and Wildlife Service, Nov. 2017, ecos.fws.gov/docs/recovery_plan/2017MexicanWolfRecoveryPlanRevision1Final.pdf.

“SAVING THE MEXICAN GRAY WOLF.” Center for Biological Diversity, www.biologicaldiversity.org/species/mammals/Mexican_gray_wolf/.