Because time is running out...

1. The Mexican wolf is the rarest and most genetically distinct subspecies of gray wolf in North America.

…in the New World, Mexican wolves appear as the most genetically distinct group, corroborating the hypothesis that this subspecies is a remnant of an ancient invasion from Eurasia and of conservation importance.[1]

…Mexican wolves represent the most genetically unique New World wolf lineage and one of the most endangered mammals in North America (Vonholdt et al. 2011; Wayne & Hedrick, 2011).[2]

2. There are only 109 Mexican wolves and eight breeding pairs in the wild, as of the most recent census (end of 2014). They are found in a single population in the Gila region of Arizona and New Mexico.[3]

3. The wild population is vulnerable to extinction due to its small size, narrow distribution and lack of genetic variation.

A species with a small population, narrowly distributed, is less likely to persist (in other words it has a higher risk of extinction) than a species that is widely and abundantly distributed.[4]

4. The wild population is exhibiting signs of inbreeding depression caused by a lack of genetic variability.

There is evidence of inbreeding depression in the experimental population (Fredrickson et al. 2007)[5] and without management action to improve its genetic composition, inbreeding will accumulate and heterozygosity and alleles will be lost much faster than in the captive population (78 FR 35664, June 13, 2013).[6]

5. There are approximately 250 wolves in captive breeding facilities. The captive population contains more genetic variation than the wild population.

Currently, the animals in the experimental population (mean kinship = 0.2548) are 50% more closely related to one another than those in the captive population (mean kinship = 0.166) due to inadequate representation of two of the three Mexican wolf lineages in the wild population (Siminski and Spevak 2014).[7]  

6. A “genetic rescue” of the wild population by releasing more wolves with targeted genetics from the captive population was proposed in 2007.[8] It has yet to happen. Only four wolves have been released in the past seven years. All of these were killed or recaptured before they could reproduce.[9]

7. The current Mexican wolf recovery plan was written in 1982 when Mexican wolves were thought to be extinct in the wild. The plan calls for establishing a wild population of at least 100 wolves in the wild as an interim measure to reestablish Mexican wolves in the wild. It was never intended to be the definition of full recovery of the subspecies.

We recognize that the reestablishment of a single experimental population of Mexican wolves is inadequate for recovery and we are fully cognizant that a small isolated wolf population such as the experimental population now occupying the BRWRA can neither be considered “viable” nor “self-sustaining” - regardless of whether it grows to a number of “at least 100” (USFWS 2010, Carroll et al. 2014). The successful reestablishment of an experimental population of Mexican wolves in the BRWRA was envisaged “as the first step toward recovery” (USFWS 1982; 63 FR 1752-1772).[10]

8. According to biologists, full recovery of the Mexican wolf will require that at least 750 wolves exist in three separate but genetically connected populations, each having a minimum of 200 wolves. 

We conclude that an appropriate set of recovery criteria for delisting the Mexican wolf would be composed of the following criteria:

1)      Population and metapopulation size: A metapopulation of at least 750 individuals that has persisted 2 successive generations (8 successive years), containing a minimum of 3 subpopulations in the wild, each with a census population of at least 200 individuals that has been maintained for 2 successive generations (8 successive years), with a stable or increasing trend in the census size of the metapopulation over the same period…[11]

9. The current rule governing the reintroduction program calls for 300-325 wolves in AZ and NM south of I-40. This is not a recovery goal. The actual recovery goal will be larger, in accordance with the best available science as required under the ESA.

Based on this best available information, we consider a population objective of 300 to 325 Mexican wolves within the MWEPA throughout both Arizona and New Mexico to be adequate as a “first step” that could contribute to recovery.[12]

10. Under any recovery scenario based on best available science, more releases of captive wolves into the wild are urgently needed. This is why more than 40 conservation groups and wildlife biologists recently sent a letter to Interior Secretary Sally Jewell, urging her to release at least five family groups into the wild by early 2016. (See attached letter.)


[1] vonHoldt, B.M. et al, A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids, Genome Research, 2011 Aug;21(8):1294-305

[2] Carroll, C. et al, Developing Metapopulation Connectivity Criteria from Genetic and Habitat Data to Recover the Endangered Mexican Wolf. Conservation Biology, 2014 Feb; 28(1): 76-86. Paper attached.

[3] See attached population estimates 1998-2014.

[4] U.S. Fish and Wildlife Service. 2014. Proposed revision to the regulations for the nonessential experimental population of the Mexican wolf (Canis lupus baileyi). Final Environmental Impact Statement. Chapter 1, p. 19

[5] Fredrickson, R. et al. Genetic rescue and inbreeding depression in Mexican wolves. Proc. R. Soc. B., 2007. Paper attached.

[6] USFWS, op cit, 1:21.

[7] Ibid, 1:21

[8] Fredrickson et al, op. cit.

[9] See attached list of releases by year: 1998-2014.

[10] USFWS, op cit, 1:17

[11] Draft Mexican wolf revised recovery plan, prepared 9/16/2011 by the Recovery Team Science and Planning Subgroup, leaked to the media. Copy attached.

[12] Ibid, 1:20.