American black bears (_Ursus americanus_) are present in Mexico, representing the southernmost populations of the species. Their presence highlights the adaptability of these mammals to various environments, extending their range beyond more commonly recognized habitats in the United States and Canada. These Mexican populations are significant for understanding the species’ ecological breadth.
Geographic Range in Mexico
Black bears in Mexico are primarily found in the northern regions, centered around the Sierra Madre Oriental and Sierra Madre Occidental mountain ranges. These areas provide the rugged terrain and forested cover bears favor. States with established populations include Coahuila, Nuevo León, Tamaulipas, Sonora, and Chihuahua. Less frequent records and unconfirmed sightings exist in Durango, Zacatecas, and San Luis Potosí, suggesting historical presence or occasional dispersal.
They often inhabit high-elevation plateaus, averaging around 2,250 meters in the Sierra Madre Occidental, characterized by oak and pine forests cut by deep valleys and canyons. This terrain offers suitable habitat for foraging and shelter, often extending from populations in the southwestern United States. Their presence is largely restricted to relatively undisturbed forested regions.
Population Status and Conservation
Black bear populations in Mexico face significant challenges, leading to their classification as an endangered species within the country. Under Norma Oficial Mexicana NOM-059-SEMARNAT-2010, the black bear is listed as “in danger of extinction,” with the exception of the Serranías del Burro population in northern Coahuila, which is designated as a “species of special concern.” This national classification differs from their global status, where the species is considered of “least concern” by the International Union for Conservation of Nature (IUCN).
Primary threats include habitat loss and fragmentation, largely due to agricultural expansion, livestock grazing, and urban development. This reduces available territory and isolates populations, limiting genetic diversity. Poaching remains a persistent issue, despite legal protections and the cessation of hunting in 1985. Human-wildlife conflicts also arise when bears are perceived as a threat to crops or livestock, leading to retaliatory killings.
Conservation efforts in Mexico include establishing protected areas and implementing anti-poaching measures. Organizations work to protect existing bear habitats and restore degraded areas, important for the species’ long-term survival. Community education and outreach programs foster coexistence and reduce conflicts. Some populations, particularly in the Sierra Madre Oriental, have shown signs of increase due to protection efforts and the establishment of Wildlife Conservation Management Units and Natural Protected Areas.
Ecological Niche
Mexican black bears are omnivores, adapting their diet to seasonal food availability within their diverse habitats. Their diet primarily consists of plant matter, including fruits, nuts, acorns, and juniper. Insects, small mammals, and carrion also contribute, though animal items represent a smaller proportion of their overall diet. This opportunistic feeding strategy allows them to thrive in various environments, from mixed forests and pine-oak woodlands to chaparral.
These bears inhabit mountainous areas with ample vegetation and water sources. They generally prefer forested regions, which provide essential food, water, and shelter. Black bears play a role in their ecosystems, including seed dispersal, which contributes to forest regeneration. Their presence can also indicate ecosystem health. In some areas, the mild climate means black bears may not undergo extended hibernation, remaining active for longer periods and utilizing winter dens for shorter durations.