Bats and People

Human cultures throughout the world and throughout history have been fascinated by these mysterious animals of the night sky. Symbols and figures of bats can be found as far back as the Mayan empire and through to present day tales such as ‘Batman’.

For many species of bat little is known. Scientists use a variety of methods to attempt to learn about these animals including affixing small radio transmitters to learn about their movement. Because of the large distances bats can travel though, and the difficulty of tracking bats in the wild, very little is known of bat movement and behavior. Populations of bats that are known to roost in large colonies can be counted and their populations monitored for growth or decline. Smaller bats that roost individually can be very difficult to find and to study though, and several species of bats are too small to affix transmitters to. For these reasons it is often difficult to understand the threats to bat populations or the best way to protect them.

As with many species, loss of habitat and human encroachment pose the greatest threat to many bats. For bats that roost in trees, destruction of forested habitat is a serious concern. Bats which roost in large colonies can be subject to disturbance by humans. A disturbance to a bat colony can jeapordize the survival of a significant portion of the population. For species that hibernate in colonies a disturbance during hibernation can cause the colony to awaken, costing them important stores of energy and significantly reducing their chances of surviving through the season. Lastly, in some countries especially those with larger species of fruit bats that provide a more significant meal, bats are considered a special source of food. In some regions bats were an important traditional source of food and reserved for special occasions, however, with increasing human populations and reduced sources of protein in regions where wild species and fisheries have been over-exploited, bats are consumed in greater numbers and their populations are under threat.

Most bat species generally pose little threat to humans. The greatest legitimate concern regarding human health and bats is their ability to transmit diseases. As mammals, they can transmit diseases such as rabies through their bite. For this reason, handling bats should be avoided or if necessary, done with heavy gloves.

Vampire bats are a much feared and misunderstood group of bats. Three species of sanguivorous, or blood-drinking bats, occur in Latin America. These bats generally feed on cattle and domestic animals such as pigs. In many cases, people who rely upon the welfare of their livestock for their livelihood have found that these bats can represent a significant economic problem. Several misguided attempts to destroy vampire bats have caused the near extermination of several non-sanguivorous bat species. In attempts to destroy vampire bats, colonies of mis-identified bats were eliminated, threatening the ecology of the region and doing little to solve the problem of vampire bats. Today, a special poison can be ‘painted’ on the neck and other regions of cattle to target the specific individuals of the species that cause livestock damage. Bats that prey upon the cattle ingest the poison leaving other species of bats unaffected.

Fruit bats in regions where fruit crops, such as figs, are a large economic crop have also found themselves the target of mis-educated eradication schemes. In regions where farmers and fruit bats both depend upon the same species for survival, farmers have often perceived these bats to pose a threat to their harvest. However, closer study shows that fruit bats generally target ripe fruits while farmers often harvest under-ripe fruits to prevent over-ripening during shipping or before sale. By leaving a small percentage of cultivated fruits to ripen, farmers can provide a source of food for fruit bats and reduce the number of under-ripe fruits eaten by bats.

A third common source of conflict between bats and humans occurs in urban or settled areas. Bats can be a nuisance when they choose human settlements for roosts, colonies of bats can leave large deposits of droppings or guano, creating undesirable smells and unsettling noise in the evenings. However, such nuisances can be easily addressed without destroying the bats themselves. Installing fixtures or conducting repairs can eliminate access to areas where bat roosts are not welcome and establishing alternative roosts for bats such as bat houses can provide roosting places for bats that are not troublesome to human occupants. Overall, as people develop a better understanding of bats’ ecological role as pollinators, seed-dispersers and insect-control they will come to see that the nuisance posed by bats are considerably less than the important ecological benefits they provide.

Article by Vanessa Parker-Geisman

Additional info by Andrew Bley ...

Bats all around the world are threatened or endangered, so what’s being done to save them? In many parts of the world there is still great prejudice toward bats. This attitude is so unfortunate not only for bats but for people as well. Bats are great pollinators and eaters of insects that we consider pests, yet their habitats are still being purposely destroyed. Since they roost in such dense numbers (Bracken Cave near San Antonio is home on any given night to over 20 million bats) it is easy to do a lot of damage with relative ease. After Mexican freetail bats took roost under the renovated Congress Avenue Bridge in Austin, Texas, people began signing petitions to have them exterminated. (Tuttle 1995) Didn’t those silly Texans realize that one shouldn’t mess with an animal that is not only harmless but is greatly beneficial? They realize it now. It’s estimated that this particular colony eats more than 27,000 pounds of insects on an average night. Now Austin has dubbed itself the "Bat Capital of America" and the bats are a popular tourist attraction. In fact, the Texas Department of Transportation now purposely builds bat-friendly bridges. Structural engineer Mark J. Bloschock said that, "We have about six million bats already living in 59 Texas bridges and we’ll be building 15 to 20 new bridges a year that together will accommodate a million new bats."

Some farmers are now building "bat boxes" to house the animals and thereby cutting down on pesticide use. People like Bat Conservation International founder Berlin D. Tuttle work tirelessly to promote bat education and appreciation.

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