Tuesday, June 5, 2012

Beneficial Bats: Why We Cannot Afford To Lose These Furry Barnstormers

by Jim Nothrop

Many people that I know are scared of bats ---- especially if they encounter them at night. The problem may be more with us than with the bats. Centuries of myths and misinformation have generated needless fears. At the same time, most people are unaware of the ways in which bats actually benefit humans without ever actually being a danger.

Having suggested a more positive image for the bat, we now need to know that in many areas of the U.S. (including the Great Swamp National Wildlife Refuge) a virulent fungus is killing many of them. To date, scientists have not discovered how this fungus (called White-Nose Syndrome) actually kills the bats, or what to do about it. But to the extent bats are being killed off in large numbers by White-Nose Syndrome, human beings are losing valuable benefits we were perhaps not even aware we have been receiving from those “scary” creatures.

There are more than 1,200 species of bats (about one-fifth of all mammal species), says Bat Conservation International, Inc. (BCI). They range from the world’s smallest mammal, the tiny bumblebee bat that weighs less than a penny, to giant flying foxes with six-foot wingspans. Except for the most extreme desert and polar regions, says BCI, bats have lived in almost every habitat on Earth since the age of the dinosaurs.
BCI confirms that only three species of bats, all in Latin America, are vampires. They really do feed on blood, although they lap it up like kittens rather than sucking it up (as horror movies suggest). Even the vampires are useful --- an enzyme in their saliva is among the most potent blood-clot dissolvers known and is used to treat human stroke victims.

Bats can be found living in almost any conceivable shelter, though BCI says they are best known for living in caves. Many species that now live mostly in buildings do so, at least in part, because of shrinking natural habitat.

Benefits of Bats

Bats are the primary predators of night-flying insects, including many of the most damaging agricultural pests and others that bedevil humans (like mosquitoes), says BCI. More than two-thirds of bat species hunt insects, and they have healthy appetites. BCI says that a single little brown bat can eat up to 1,000 mosquito-sized insects in a single hour, while a pregnant or lactating female bat typically eats the equivalent of her entire body weight in insects each night.

BCI notes that almost a third of the world’s bats feed on the fruit or nectar of plants. In return for their meals, these bats are vital cross-pollinators of countless plants. Bats that drink the sweet nectar inside flowers pick up a dusting of pollen and move it along to other flowers as they feed. BCI reports that a few of the commercial products that depend on bat pollinators for wild or cultivated varieties include: bananas, avocadoes, dates, figs, peaches, mangoes, cloves, cashews and balsa wood. Bats also are major seed dispersers in the regeneration of rainforests.

What Is the “White-Nose Syndrome” That Is Stealthily Killing Our Bats?

The U.S. Fish & Wildlife Service reports that in February 2006 some 40 miles west of Albany, N.Y., a caver photographed hibernating bats with an unusual white substance on their muzzles. He noticed several dead bats. The following winter, bats behaving erratically, bats with white noses, and a few hundred dead bats in several caves came to the attention of the New York Department of Environmental Conservation biologists, who documented White-Nose Syndrome in January 2007. More than a million hibernating bats have died since. Biologists with state and federal agencies and organizations across the country are still trying to find the answer to this deadly mystery.

Sick, dying and dead bats have been found in unprecedented numbers in and around caves and mines from New Hampshire to Tennessee. In some hibernation sites, 90 to 100 percent of the bats are dying. While they are in the hibernation site, affected bats often have white fungus on their muzzles and other parts of their bodies. They may have low body fat. These bats often display strange behavior ---- moving to cold parts of the hibernation site, flying during the day and during cold winter weather when the insects they feed upon are not available, and they exhibit other uncharacteristic behaviors.

Despite the continuing search by numerous laboratories, and state and federal biologists, to find the source of this condition, the cause of the bat deaths remains unknown. A newly discovered cold-loving fungus (Geomyces destructans) does invade the skin of the bats and may be part of the answer. Scientists are exploring how the fungus acts and searching for a way to stop it. Answers to these questions are needed very soon.

About the Author. Jim Northrop is a long-time member of and volunteer for the Great Swamp Watershed Association (GSWA). A resident of Madison, New Jersey, he has served on GSWA's Board of Trustees and currently lends his support to the organization's Land Use Committee and it Communications Taskforce. Jim has authored many articles that appear in GSWA's biannual newsletter, its monthly eNewsletter, its website, and its several blog outlets.

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