North American Bats in Trouble

Bats--we all love them. They figure prominently in Gothic and Halloween art as well as in some of our most memorable horror movies. After all, doesn't Count Dracula take the shape of a bat and often fly to the abode of his victims?  And doesn't he wrap his cloak about himself like a bat wraps its wings when getting ready to sleep?

Some time last year, I learned that a nearby state park was no longer granting public access to its popular caves. The reason? Authorities wanted to protect the bats that lived in them from the spread of a lethal fungal infection known as white-nose syndrome, which invades and then breaks down the animal's nose and wing tissues as well as compromising the immune system. It is believed that human intrusion into caves where bats gather and hibernate is helping to spread the fungus. 

I really didn't know how serious the threat to the bat population was until this past weekend when Public Radio International's (PRI) Living on Earth aired a segment entitled America's Bats on the Brink, during which program host Steve Curwood interviewed Katie Gillies, the Imperiled Species Coordinator for Bat Conservation International; an organization with its offices in Austin, Texas.

Gillies began by explaining that erratic bat behavior has been reported this winter from the Great Smoky Mountain National Park, where the animals have been observed, not only flying in search of food, but even flying perilously close to human beings, who were forced to shoo them away with fishing poles. One trail walker reported being hit in the forehead by one. Gillies went on to explain that bats fall into a deep slumber during the winter months, during which their heart rate and body temperature drop significantly. White-nose syndrome, she went on to say, irritates the animals to the point that they repeatedly awaken from hibernation, thereby speeding up their body processes, which in turn, causes the onset on malnutrition. Since bats feed on insects their excursions into the cold winter night in search of food is an exercise in futility that only serves to weaken their malnourished bodies even further.

White Nose Syndrome, which is believed to have origins in Europe, has now spread to some 19 American States and at least four Canadian provinces. When asked how much damage the fungus has done to bat populations in places where the animals congregate she replied that some sites have seen a 99 percent fatality rate; this from a problem that was only discovered between 2006 and 2007. "We are witnessing what may well be an extinction event," she admitted. 

Equally troubling is an announcement that was made by the National Park Service through Mammoth Cave National Park Superintendent Sarah Craighead on January 16 of this year. "It grieves me to make this announcement," she said, "a northern long-eared bat showing signs of White-Nose Syndrome was found in Long Cave in the park.The bat was euthanized on January 4 and sent for laboratory testing. Those tests confirmed white-nose syndrome."  Mammoth Cave National Park is located in south/central Kentucky. 

Although those of us with darker imaginations tend to think of bats quite fondly, we're not the only ones who are concerned with the animals' survival as they are a great asset to agriculture; this, due to their diet which focuses almost exclusively on insects. According to information Ms. Gillies gave during her Living on Earth interview, the average bat consumes between four and eight grams of insects per night. Further, the creatures collectively consume approximately 7.5 metric tons of insects annually. According to the bat-conservation official, Science Magazine has estimated that the animals provide a $23 billion benefit to farmers in the United States alone on an annual basis. The tragic side of all this is that white-nose syndrome has already dealt a serious blow to the U.S. bat population by killing approximately 5.7 million of these benevolent beings, thereby bringing some species into consideration for the Endangered Species List. Just how the decimation of bat populations will affect agriculture, insect populations and the environment in the future is anybody's guess. 

Steps are being taken to stop or at least slow the spread of the fungus. As mentioned earlier, some caves have become off limits to human intruders while at others, authorities only allow access after stepping through a disinfectant. Still, the future of many of our beneficial and beloved North American bats is in jeopardy. We can only hope that the dreaded white-nose syndrome fungus will cease its spread. After all, what would Halloween and our Gothic imagination be without bats?      

References 

Mammoth Cave National Park News Release

Washington Post: Erratic Bat Behavior at Great Smoky Mountain Park


 <B>Living on Earth: Listen to the program

Photo courtesy Free Digital Photos Dot Net