Reports are cropping up around the country about black bear sightings in January. While this might not sound too unusual to us here in the southern Big Bend area, it is very unsettling to people in other places such as Nevada’s Tahoe area. More than one bear has been recently reported at ski resorts, where the winter skiing season brings many people in for races and recreation. Interruptions in bear hibernation periods are now being documented globally. And they correlate with events of climate change in their home regions. Increasing bear encounters parallel these observations.
The three main triggers that activate hibernation behavior in an animal are changes in air temperature, food availability, and day length (called photoperiod). Researchers are finding that changes in a region’s climate are affecting hibernation behaviors around the world.
Activity of brown bears in the Spanish mountains has been documented now for several years. The decline in snowfall, the time that snow fall remains on the ground, and warming in valleys make access to food more available during the time which these bears would normally hibernate. The most active bears are mothers with cubs. However, the hibernation period for even mature adult male bears has been getting shorter every year.
Mark Wright, science adviser to the World Wide Fund for Nature, commented, “It does not in itself prove global warming, but it is certainly consistent with predictions of it. What is particularly interesting about this is that hitherto the warming has seemed to be happening fastest at the poles and at high latitudes, and now we’re getting examples of it happening further south, and heading towards the equator.”
Along with other hibernating species, bears rousing from hibernation require a relatively large amount of metabolic energy. The animals typically don’t have much fat reserve to spare after giving birth to cubs. The additional stress on their bodies can have deleterious results, make them aggressive, and, in extreme environments, may lead to death.
The black bear is extremely adaptable. Most hibernate depending on local weather conditions and availability of food during the winter months. In regions where there is a consistent food supply and warmer weather throughout the winter, such as in the southern Big Bend area, bears may not hibernate at all or for only a very brief time. Females give birth and usually remain denned throughout the winter, but males and females without young may leave their dens from time to time during winter months.
Two subspecies of the American Black Bear can be found in southern Texas: the Mexican Black Bear (Ursus americanus eremicus) and the New Mexico Black Bear (subspecies U. a. amblyceps). Both have been reported in West Texas, usually in desert scrub or woodland habitats within scattered mountain ranges, such as the Chisos and Guadalupe Mountains. However, tracks, scat and sightings of black bear have been also documented outside of these mountainous areas, including lowland scrub areas in and outside of the Big Bend National Park.
Due to mild climate and more prevalent food, black bears usually do not hibernate in southern Big Bend. Bears in Big Bend National Park may be dormant for just three to four months (January-March) each year. However, a few sporadic sightings have been reported in recent months (November, December of 2013 and January of 2014). Consequently, hikers and hunters should be aware that black bears might be encountered, and should review how to avoid and/or react encounters with black bears.
The Black Bear is on the Texas state endangered species list. Texas Parks and Wildlife Department biologists encourage people to report recent bear sightings to their local or central office. Research is currently underway by the TPWD to determine the status of Black Bears in Texas and they can be contacted at this phone number: 1-800-792-1112.