This Halloween, Real Bats Are Scarce
by Abram Katz | Oct 29, 2010 7:46 am
Posted to: Higher Ed, Science/ Medical
Most of us don’t pay much attention to bats except around Halloween, when bat-like rubber effigies appear on posters, in “haunted” houses, and on devilish front yard decorations.
And most non-bat experts have never seen an actual bat in the wild or backyard.
But they’re there. For now.
However, bats are succumbing to white nose syndrome, a fungal disease that leaves the little mammals covered with a deadly cloud of “snow.” And fewer bats mean more insects. Loads more.
White nose was first detected in upstate New York caves in the winter of 2006. Since then it has spread to Connecticut and all the way to the Midwest.
Miranda B. Dunbar, newly appointed assistant professor of biology at Southern Connecticut State University, has been studying bats for years. Her main interest is in how bats hibernate.
Eight species of bat are indigenous to Connecticut. They are small, nocturnal insectivores that want to run into you less than you want to encounter one of them.
“The prognosis for bats in Connecticut is not bright,” Dunbar said.
Although little bat research has been conducted in Connecticut so far, biologists know that white nose syndrome is eradicating the little brown bat, (Myotis lucifugus), a tiny creature that breeds in warm attics, barns and any other dark, private roost.
The origin of the white nose fungus is obscure and no one knows how it spreads from one roost to another, she said. Spelunkers may introduce spores. However, preventing people from entering caves has not proven effective in controlling the disease, Dunbar said.
The other common Connecticut bats are the red bat, the hoary bat, the large brown bat and the northern bat. The little brown bat is the most common. The hoary bat, at a mere 30 grams is the state’s largest. That’s about one ounce.
“They’re all wings,” Dunbar said.
Bats are one of nature’s ways of keeping insect populations under control.
They dine on certain insects that attack crops, and eat other irritants, like gypsy moths. Bats also consume literally tons of mosquitoes.
A mosquito could weigh anywhere from one one-hundred- thousandth of an ounce to three ten-thousandths of an ounce. A bat may eat one to two body masses of insects a night, Dunbar said. To maintain that rate the little brown bat needs to eat about 600 mosquitoes an hour.
So if one little brown bat vanishes, that’s hundreds of thousands of mosquitoes free to roam and feed on human blood.
“White nose syndrome is having a huge impact and we know so little about it,” she said. “We’ve seen massive increases in insects, including crop pests, during the summer,” she said.
Boston University biologists estimate that the little brown bat may disappear from the Northeast in 20 years unless methods can be found to fend off the fungus found to cause white nose syndrome, Geomyces destructans.
Most Connecticut bats, like many other mammals, hibernate during the winter. This is when the fungus invades the animals. Dunbar said it is thought that hibernation, along with lowering respiration and temperature, may also reduce the bats’ immune systems.
Perhaps the bats are physiologically triggered to wake up, to heighten the immune response, or the fungus disturbs them. When the bats awaken during winter they rapidly consume the fat need for hibernation and they starve to death.
Meanwhile, although most people never notice them, bats are all around us, even in New Haven. During summer, watch streetlights, Dunbar said.
Moths and other insects gather there and every few minutes a bat is likely to swoop in for a fast meal, she said.
Unless you watch carefully, the bat can be mistaken for a large moth or a small bird.
Dunbar said that night games in lit stadiums are a great place to watch bats.
Bats do not want to drink your blood (the few that do live south of the United States and prefer livestock) or get tangled in your hair. Only a very small percentage carry rabies.
Dunbar said she was initially assigned a project on bats as an undergraduate at the University of Illinois in Springfield. “I started working on it a couple of days before it was due and I was fascinated. I started out dreading them,” she said.
Dunbar did graduate work at the University of Missouri in Springfield, and received her doctorate in bat biology at the University of Regina in Saskatchewan, Canada.
Her most recent research, on bat hibernating habits at different latitudes, was published in the March edition of the Journal of Comparative Physiology B.
Bats are not “flying rats.” Not even close. Bats are difficult to categorize, but they appear to be related to shrews.
Bats also comprise about a quarter of all mammal species. They live on every continent except Antarctica.
“Most people are afraid of bats. It’s a silly fear. It is because we don’t see them,” Dunbar said. “Bats want to avoid people just like any other wild animal.”
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