Post by L Roebuck on Jun 22, 2006 9:53:22 GMT -5
Inside the BAT cave
Batman isn't the only creature of the night who resides in a cave. Colonies of 30,000 to 40,000 gray bats call Missouri caves home. Unlike their big, brown cousins they are rarely seen and only come out at nightfall to use their powerful sense of hearing
By Susan Atteberry Smith
FOR THE NEWS-LEADER
Their calls register at a frequency so high, the human ear can't detect it.
Yet their ears work so well, they can "hear" the size and shape of their next meal — even before they catch it. In the dark.
They're bats, and because "they're so good at what they do," they fascinate scientists like Lynn Robbins, a Missouri State University biology professor who has studied these nocturnal mammals since the 1970s.
And, of the dozen or fewer species that call Missouri home, the gray bat, an Ozarks native, is just as fascinating as the rest of its relatives.
GRAY BATS KEEP OUT OF SIGHT
Bats are elusive, tucking into crevices and camouflaging themselves in trees.
"Most people aren't even aware how close we live with bats on a regular basis, because bats are asleep during the daytime and hiding behind shutters, behind eaves or in attics," says Rick Clawson, a Missouri Department of Conservation resource scientist who also has studied bats since the '70s.
Yet gray bats are even less likely to be seen by the common person.
"If people see bats flying up and down their neighborhood streets at dusk, they're probably big brown bats," Clawson says.
Riddled with caves, the Ozarks of southwest Missouri and northern Arkansas give gray bats the cover they need. Unlike big brown bats and other Missouri bats, which come out of hibernation to roost in trees, attics or towers in the spring and summer, gray bats stay in caves year-round.
"It is the only bat in Missouri that lives in caves all year," Clawson says.
Flying out at nightfall to sweep the air for insects, they might venture 10 to 12 miles from home, Clawson says, but it's usually only people living near rivers and lakes who stand a chance of catching a glimpse of them.
"It's a bat that eats only insects, and most of its insect diet is found around water," Robbins explains.
And the gray bat, living up to 30 years in large colonies of 30,000 to 40,000, can put away a lot of insects, considering an adult member of the species usually weighs less than half an ounce.
"They'll catch 40 or 50 bugs in an hour — very fast, very quick," Robbins says. "All with sonar."
Robbins is referring to echolocation: the ability all bats have to use their ears to find their way — and their prey — in the dark.
"They basically hear in color, it's so good," Robbins says of this specialized sense. "Each species has a slightly different frequency suite, so they're feeding on a slightly different group of insects."
He and his students at Missouri State know this because they have recorded the calls of bats, matching them by species. They have also banded and attached radios to bats to track their habits and, in doing so, have disproved at least one assumption about the gray bat: that it will automatically fly to water to find food.
About four years ago, Robbins and some students released a radioed gray bat they'd caught at Sequiota Cave. Then they stationed themselves along the James River and near Lake Springfield, thinking the bat would head straight to water.
"It disappeared," Robbins says. "We couldn't find it. ... For the next three nights, we tracked the bat. It went to the mall."
The lights at Battlefield Mall attract bugs, Robbins says, "so (the bat) changed its natural behavior to go where the bugs were."
Full Article
www.news-leader.com/apps/pbcs.dll/article?AID=/20060622/LIFE06/606220312/1037
Batman isn't the only creature of the night who resides in a cave. Colonies of 30,000 to 40,000 gray bats call Missouri caves home. Unlike their big, brown cousins they are rarely seen and only come out at nightfall to use their powerful sense of hearing
By Susan Atteberry Smith
FOR THE NEWS-LEADER
Their calls register at a frequency so high, the human ear can't detect it.
Yet their ears work so well, they can "hear" the size and shape of their next meal — even before they catch it. In the dark.
They're bats, and because "they're so good at what they do," they fascinate scientists like Lynn Robbins, a Missouri State University biology professor who has studied these nocturnal mammals since the 1970s.
And, of the dozen or fewer species that call Missouri home, the gray bat, an Ozarks native, is just as fascinating as the rest of its relatives.
GRAY BATS KEEP OUT OF SIGHT
Bats are elusive, tucking into crevices and camouflaging themselves in trees.
"Most people aren't even aware how close we live with bats on a regular basis, because bats are asleep during the daytime and hiding behind shutters, behind eaves or in attics," says Rick Clawson, a Missouri Department of Conservation resource scientist who also has studied bats since the '70s.
Yet gray bats are even less likely to be seen by the common person.
"If people see bats flying up and down their neighborhood streets at dusk, they're probably big brown bats," Clawson says.
Riddled with caves, the Ozarks of southwest Missouri and northern Arkansas give gray bats the cover they need. Unlike big brown bats and other Missouri bats, which come out of hibernation to roost in trees, attics or towers in the spring and summer, gray bats stay in caves year-round.
"It is the only bat in Missouri that lives in caves all year," Clawson says.
Flying out at nightfall to sweep the air for insects, they might venture 10 to 12 miles from home, Clawson says, but it's usually only people living near rivers and lakes who stand a chance of catching a glimpse of them.
"It's a bat that eats only insects, and most of its insect diet is found around water," Robbins explains.
And the gray bat, living up to 30 years in large colonies of 30,000 to 40,000, can put away a lot of insects, considering an adult member of the species usually weighs less than half an ounce.
"They'll catch 40 or 50 bugs in an hour — very fast, very quick," Robbins says. "All with sonar."
Robbins is referring to echolocation: the ability all bats have to use their ears to find their way — and their prey — in the dark.
"They basically hear in color, it's so good," Robbins says of this specialized sense. "Each species has a slightly different frequency suite, so they're feeding on a slightly different group of insects."
He and his students at Missouri State know this because they have recorded the calls of bats, matching them by species. They have also banded and attached radios to bats to track their habits and, in doing so, have disproved at least one assumption about the gray bat: that it will automatically fly to water to find food.
About four years ago, Robbins and some students released a radioed gray bat they'd caught at Sequiota Cave. Then they stationed themselves along the James River and near Lake Springfield, thinking the bat would head straight to water.
"It disappeared," Robbins says. "We couldn't find it. ... For the next three nights, we tracked the bat. It went to the mall."
The lights at Battlefield Mall attract bugs, Robbins says, "so (the bat) changed its natural behavior to go where the bugs were."
Full Article
www.news-leader.com/apps/pbcs.dll/article?AID=/20060622/LIFE06/606220312/1037