Humans
blind to bats' plight
Winged mammals don't get the respect they deserve
By Callan Bentley
Flat Hat Variety Editor
Walking by Ewell Hall Tuesday night, I caught a glimpse of something flitting through the air, all fur and leathery wings. It was a sight I've been waiting to see for a while: the first bat to come out of hibernation this year.
Bats are without a doubt an odd and fascinating group of animals, but to most people a bat is something to duck away from, to shut out, to kill. As bat biologist Merlin Tuttle put it, "Fear of things we don't understand is at least a well-documented aspect of human behavior, and that is precisely the problem with bats."
In order to alleviate the many misconceptions about bats (and hence the fear that surrounds their presence), this week's column is dedicated to these amazing animals. It should be noted that while I describe most things in this column as "amazing," the term has never applied more than with bats. Bats are some of the finest animals that evolution has ever come up with.
Bats are the only mammals that can fly, a trait that has earned them the honor of being placed in their own order, the Chiroptera. All living bat species fall into one of the two groups of bats, the Megachiroptera (the so-called flying foxes) or the Microchiroptera (all other species). Only members of the latter group will be found in Williamsburg, as the flying foxes are distributed only in tropical climates.
Although by looking at a bat, one might think of a flying mouse and group it with rodents, the bats are actually most closely related to the primates. When Linnaeus formulated the taxonomic system, he was so impressed by the similarities between bats and primates that he originally placed them in the same group! Both bats and primates give birth to poorly developed young and nurse them from pectoral breasts. It is evident now however, that these basic similarities don't mask the substantial differences between the groups. Bats and primates have both descended from a common shrew-like ancestor, but belong to different orders.
There are nearly 1,000 kinds of bats in the world, which means that fully a quarter of all mammal species belong to the Chiroptera. They are found everywhere but in extremely dry deserts and extremely cold polar regions. They are an incredibly diverse group of animals. Thailand's bumblebee bat weighs less than a penny, making it the world's smallest mammal. Some flying foxes of the Old World tropics tip the scales in the other direction with wingspans extending past six feet. They come in many colors, some so brightly patterned as to be christened "butterfly bats." Others have fabulously contorted faces, with enormous ears, blade like "nose leaves," and other intricately sculpted facial features which serve the bat's sense of navigation by focusing sounds.
Most bats communicate and navigate by using high-frequency sounds. They emit these sounds, which are mostly out of the range of human hearing, in short, rapid-fire bursts, and then listen for their return. When the echoes bounce back, the bats interpret them into a sense of where things are and where things aren't. Using nothing but this sound, bats can "see" everything but coloration, down to something as small as a human hair. This does not mean that bats are blind, though this myth is commonly held as fact. Many of the flying foxes have excellent vision, in fact.
Bats mate just before hibernation begins in the fall, and in the spring females form large nursing colonies. They give birth to their young over about a month and a half, and weaning their young as soon as three weeks after that. This means that bats are the slowest reproducing animals for their size on Earth. Most mother bats rear only one young per year. This does not prove detrimental, as bats are exceptionally long-lived, some lasting for longer than 30 years.
Some nursing colonies can get extraordinarily dense, in excess of 500 young per square foot of cave wall space, extending for hundreds of square feet around. Despite this tight-packed lifestyle, mother bats remember the location of their young to within a few inches. As the mother returns from feeding, her child recognizes her voice, raises itself up, and calls to aid in her navigation.
Bats live in a great many types of shelters, though they are best known for occupying caves. Many have taken to roosting in buildings due to a lack of alternatives. Many people have put up bat-houses in their yards to give bats a safe place for roosting. A bat-house is a simple affair; closed on the sides and roof, but open on the bottom for bats to fly in. Inside are several different kinds of divisions which the bats grip onto while they sleep.
Almost all bats in Williamsburg are insect-eaters, like 70 percent of the world's bat species. Other bats feed exclusively on nectar or fruit, while a few are carnivorous, catching small vertebrates. A very small number are vampire bats, which live in Latin America and lap up the blood of larger mammals. Across the globe, bars are the major predators of nighttime insects, including mosquitoes. One individual mouse-eared bat (the most widespread North American species) can eat up to 600 mosquitoes in a single hour of flying. You can imagine how much a large colony can consume in an entire night's foraging. The 20 million bats that live in Bracken Cave in Texas eat a quarter of a million pounds of insects of more every night.
Bats also figure importantly in the process of pollination. In fact, if it were night for bats, many of the world's most economically valuable plants would perish. Some of these include bananas, avocados, peaches, mangoes, balsa wood, cloves, and agave; the plant from with tequila is derived.
The importance of bats, both to the ecosystem and to plants humans depend on, is incredible. It is a travesty that people should be so foolish as to poison and shoot bats as if they were disease-ridden pests. One of the most heinous examples of this disregard for bats' importance occurred in the 1960s at Eagle Creek Cave, Arizona. In 1963, the world's largest bat colony roosted there, totaling close to 30 million Mexican free-tailed bats. In just six years, shotgun shooting of the bats reduced their numbers to 30,000. That's a 99.9 percent decline. The lost of bats there leaves 350,000 pounds of insects uneaten every night, drastically altering the fragile ecosystem and increasing the number of mosquito bites received by each of the shotgun-wielding executioners outside the cave. These sorts of destructive acts are still common. People need to learn that bats are to be marveled at, not blown away.
Much of humanity's fear of bats stems from rumors of rabies. The fact is that less than one-half of one percent of all bats ever contract rabies. This tiny portion is far more likely to die in isolation than to ever come into contact with humans. In more than 40 years, public health records for this continent show that only 16 people have died from bat-borne diseases, mainly rabies. This means that the odds of anyone dying from a disease they got from a bat are far less than one in a million. For people who do not handle bats, there is no reason to worry.
There are six species of
bat that include the Williamsburg area in their range. There are many excellent
bat-watching locales in Colonial Williamsburg and on campus. The field in front
of the Governor's Palace is particularly good, as are other open areas. At the
Sunken Gardens, you can watch bats as they circle around, scooping up the insects
which mass on the lights lining the field's edge. If you want to interact with
the bats, toss a small pebble up as they fly by. Mistaking it for an insect,
they will likely dive towards it, but dart away at the last second upon realizing
what it actually is.