A San Bernardino flying squirrel is small. Photo by Darleen Ortlieb Frechen, courtesy of the Center for Biological Diversity
A San Bernardino flying squirrel is small.
Photo by Darleen Ortlieb Frechen, courtesy of the Center for Biological Diversity

Last week, the Center for Biological Diversity filed a lawsuit to force the federal government to determine whether each of nine species are endangered or threatened. Among the nine is the San Bernardino flying squirrel, a native to the local Southern California mountains.

CBD had submitted petitions requesting the U.S. Fish and Wildlife Service to assess the status of these species populations. Although the agency did publish notices that these populations should be evaluated, nothing has occurred. The acknowledgement of CBD’s 2010 petition for the flying squirrel was published in 2012; no determination has been announced. The service is now almost three years overdue in making the required 12-month finding to decide whether protection will be granted.

This rare, truffle-eating flying squirrel is threatened by climate change, forest habitat destruction and predation from domestic cats. It has disappeared in recent decades from one of the two mountain ranges it lives in near Los Angeles, according to the CBD filing.

“If these amazing flying squirrels don’t get Endangered Species Act protection, global warming could push them out of their last mountain refuge,” said Shaye Wolf, CBD’s climate science director. “The federal government needs to act before these unique animals disappear forever.”

The San Bernardino flying squirrel is a small squirrel that lives and glides through mixed-conifer forests between 4,000 and 8,500 feet in elevation. A subspecies of the northern flying squirrel, the San Bernardino flying squirrel’s historic range was the San Bernardino and San Jacinto mountains of Southern California. Over the last 100 years, however, no verifiable sightings of the species have occurred in the San Jacinto Mountains.

Flying squirrels get their name from a furred membrane called the patagium that extends from the wrists to the ankles, thus enabling them to easily glide between trees. They can glide through the air between trees at distances up to 300 feet.

According to the FWS, moisture is important for the squirrel’s habitat, which tends to be near streams or springs that promote the growth of truffles. As urban development usurps forests, the squirrel’s remaining mountain habitat decreases and the threat of predation from domestic cats increases. As these changes occur, the squirrel is forced to higher elevations, eventually running out of habitat to occupy.

Based on these threats to the San Bernardino flying squirrel, on Aug. 24, 2010, CBD submitted a petition to FWS to list the species as endangered or threatened under the ESA.

On Feb. 1, 2012, FWS issued a 90-day finding on the CBD’s petition to list the San Bernardino flying squirrel. The finding concluded that CBD’s petition presented substantial scientific or commercial information indicating that listing the San Bernardino flying squirrel may be warranted.