If it ain’t broke, don’t fix it much less destroy it. But the
human animal seems hell bent on fixing or destroying a system that
has worked for thousands of years. We are destroying one of our
most efficient insect control systems: bats.
I recently watched in awe as an estimated 12 million bats left a
west Texas cave. They left over a two-hour period in a slowly
rising column 60 feet wide and 30 feet high. They headed southeast
in a long, twisting line that resembled smoke as it disappeared in
the distance. They travel up to 50 miles away each night hunting
beetles, mosquitoes and other insects, usually over open farm
Someone figured out that they consumed enough insects every
night to fill nine truck trailers pulled by 18-wheelers. There are
about 100 million bats using a dozen caves in west Texas. They
consume about 15 tons of insects a night.
So what do people do to these no-cost, extremely efficient
We shoot them and seal entrances to their caves. Yet, they are a
far more efficient insect control system than electric bug zappers
(if they work at all), or pesticides that poison our
A naturalist at the cave said most bat shooters have been
drinking, and they want to see how many bats they can kill with one
shotgun shell. In recent years, cave bat populations have dropped
sharply. The number using Carlsbad Caverns in New Mexico has
dropped from 8 million to 500,000. That is more than 51/2 fewer
trailer loads of insects no longer caught each night.
Some people think bats spread AIDs, but there is no proof of
this. A very few are rabid, but no more than other mammals. In the
past 40 years, 15 people in Canada and the U.S. have died of rabies
contracted from bats.
Other people are afraid bats will fly into their hair. Bats
catch small insects in the dark with a very sophisticated method of
echolocation, and they want less to do with you than you do with
them. They aren’t about to blunder into your hair. But people throw
firecrackers into caves to panic bats. The confined explosions
destroys the bats’ echolocation, and they starve. The
blood-drinking vampire bat is a tropical animal and very few are
found even as far north as Texas.
About 90 percent of the bats in the cave we watched were females
that have one “pup” a year that flies when five weeks old. Most of
them are Mexican free-tailed bats that have short tails. We watched
red-tailed hawks swoop through the clouds of bats and catch one.
The naturalist said peregrine and Cooper’s hawks, and owls also
take bats as they leave or return to the cave.
Minnesota does not have any caves that are home to large numbers
of summering bats. The little brown bat, our most common bat, does
gather in small groups to have young. In winter, larger numbers of
them gather in caves and sewers to hibernate. Most of our other
bats live solitary lives and migrate each fall.
But we can encourage bats by building bat houses. They have been
successful at some of our state parks, and plans are available in
the DNR’s “Woodworking for Wildlife,” available by calling
651-296-6157 or 1-800-766-6000.
Everyone is eager to help cuddly pandas, but toothy,
night-flying bats are another story. Their pictures often are taken
after someone has just grabbed them. Like most animals, they defend
themselves and are showing teeth. But when one of the Texas bats
bumped into another and fell to the ground, the naturalist picked
it up and it quickly became quiet. We stroked the bats with our
fingers, and they made no attempt to bite. And their fur is very
soft. And they eat mosquitoes.