Why Mexico?

In Mexico and northern Guatemala are a series of globally important dry broadleaf and pine forests home to an exceptional level of small mammal diversity. In terms of threatened small mammal conservation, Mexico is the number one priority region in the world. This region has by far the highest overall small mammal species richness (264 species) and the highest number of globally threatened species (62 species) of any of the SMSG’s Key Regions. Furthermore, the most notable feature of this diversity is the high number of globally threatened small mammals with severely restricted ranges that live here. Mexico is the country with the world’s highest number of Alliance for Zero Extinction sites triggered by small mammals, with a total of 31 AZE trigger small mammal species. Particular concentrations of these AZE species can be found on the Baja California peninsula as well as in the southern Mexican dry forests. Comparing this to Indonesia, the country with the second most AZE trigger small mammals (13 species), clearly demonstrates the global importance of Mexico. Southern Mexican forests are also home to one of the top 100 EDGE mammals: Nelson’s small eared shrew (Cryptotis nelsoni).
The small mammal fauna of this Key Region is dominated by 130 species of new world mice and rats from the Cricitedae family. Among these is the large number of globally threatened deer mice from the genera Habromys and Peromyscus, as well as the giant deer mice Megadontomys. Other notable features include 40 species of pocket mice and kangaroo rat from the Heteromyidae family and 35 shrew (Soricidea) species.


Urban development, tourism, agricultural plantations and ranching are all high-impact threats to the dry forests of southern Mexico. These pressures in turn impact on small mammal populations, many of which are extremeley restricted in geographic range and therefore highly vulnerable to habitat loss.


In terms of small mammal conservation, the main response needed is increased protection of habitats both within and outside of the existing protected area network.
Surveys are also desperately needed to map at fine scale the distributions of the globally threatened small mammals and to assess how this relates to the Mexican protected area network and its management effectiveness. There are 11 Data Deficient species in this Key Region.

Future Plans

The SMSG recently convened a workshop in Puebla, Mexico. With the generous support of Africam Safari, who hosted the workshop, experts in Mexican small mammals and conservation met to share knowledge and develop a plan to expand and promote conservation and research in this Key Region.