Although it is a prevalent myth, there is no evidence of bats flying into people’s hair. The belief probably stems from common bat flight behaviors that are easily misinterpreted. Bats are naturally curious, and if you walk down a forest trail on a warm summer evening, it is not uncommon to have a bat fly very near to you before veering off. Bats become accustomed to flying certain pathways, and an unusual object such as a human being in a pathway may be a natural curiosity.
Another situation that might suggest this behavior occurs when many bats are disturbed in an enclosed area, such as a small cave roost. With lots of bats flying at once in a confined space, some may not only fly very close but occasionally even brush against people who get in the way. They are in fact trying to escape rather than to attack, and human hair holds no particular attraction for them. However, should a bat brush heavily against a particularly bouffant hairdo, it could conceivably become entangled and might well lead to an experience that gets handed down and expanded upon from generation to generation.
Brock Fenton, a Canadian bat biologist, has recently suggested two additional scenarios that might be origins for this myth. Once again imagine that summer evening, but this time recall a site where you have been surrounded by a swarm of small flying insects, such as mosquitoes or midges. It is certainly possible that such a congregation could attract a hungry bat, and in the process of feeding, the bat might come uncomfortably close to the human at the center of the swarm.
The other situation will be familiar if you have ever seen a bat trapped inside a room. The bat circles, obviously seeking an escape route, and as it approaches each wall, it slows almost to a stall, at which point it swoops low to regain speed and increase lift and thrust to continue the flight. These swoops can bring the animal very close to human occupants of the room and might easily be misinterpreted as attacks.
Bats are not a threat to humans in the sense of mounting a direct attack or flying into your hair. With the rare exception of vampire bats in Latin America, they will almost never approach a human with anything other than curiosity in mind. They can, however, harbor diseases that can affect humans.
The most serious disease bats can carry is rabies, and the potential threat of rabies argues against handling bats, particularly if they are acting strangely or let you approach without trying to escape. This said, it should be stressed that bats are no more likely to harbor rabies than many other mammals, and much less so than some species. In the wild only a fraction of a percent of bats are rabid. Also bats are much more likely to transmit rabies to other bats than to any other species of mammals. In most areas where rabies outbreaks occur, the strain of the virus has been traced back to dogs, cats, raccoons, skunks, or other mammals.
It is theoretically possible for any species of bat to become rabid. However, the likelihood is much greater for vampire bats than for others, simply because they come into direct contact with the blood of other mammals every day. Insectivorous species in northern latitudes also occasionally harbor the virus but never for very long, because they are also killed by the disease. Fruit eaters in the tropics almost never have rabies.
Another disease occasionally associated with bats is histoplasmosis, caused by the fungus Histoplasma capsulatum. It is possible for humans to become infected with this disease by breathing in the spores, which are sometimes found in large, dry, dusty accumulations of bird or bat droppings. Avoidance of these situations should virtually eliminate the danger of contracting this disease. If it is necessary for you to remove large accumulations of dry guano from an attic or other enclosed area, using a respirator should protect you from this risk.
Most species of bats also harbor ectoparasites such as mites and occasionally fleas or ticks. However, most such ectoparasites are highly host specific, meaning they live only on bats, and in fact frequently only on a single species of bat. Thus they pose no threat to humans. I have handled thousands of bats and been exposed to these ectoparasites many times over the years, with nary an ill effect. The most common of these are frequently bat flies, which may leave the bats and scamper across your hand or arm, but they do not bite and eventually leave of their own accord.
Diseased bats can theoretically be found anywhere. That is why bats that are out of place, acting strangely, or unafraid of humans should be avoided. However, the odds of you being killed by a bat-borne disease are much less than one in a million, and you face greater danger from honeybee stings or bathtub falls than from any sort of health risk from bats.
Humans have created havoc with the environment of most other kinds of animals, but there are a few species that have adapted comfortably to the ways of people. Several species of bats have taken to buildings as if they own the places. Attics, barns, outbuildings, and the like mimic the ancient snag or cave roosts that were probably the ancestral refuges of these species. Such environments provide the requisite dark, relatively temperature-stable refuge from predators that most species of bats require for a daytime retreat. The fact that these quarters are shared with a family of Homo sapiens below is of little consequence to the bats. All they need is a tiny entrance and exit hole and freedom from disturbance.
The single most common bat problem that people are likely to face is the appearance of a bat inside the house. This can be startling at first. However, there is little to fear, and easy remedies are at hand. The bat is likely to be as confused and upset as you are. It is undoubtedly lost and trying to make its way outside, so all you need to do is help it along by opening doors and windows and letting it find a way out. If this fails you can gently put a towel over the animal when it has landed on the wall or floor, then carry it outside to release it.
The other common bat-related problem is a colony using the attic of your home. The only solution here is to build the unwelcome visitors out by finding and blocking all potential entrances with bird netting. Of course this needs to be done when the bats are not present. The best time to do repairs is during the winter, when the bats will likely have moved to cooler quarters to hibernate.
If your bats are year-round residents, you will need to do the repairs at night, when they are out foraging. This will also require ensuring that there are no young left behind so that you do not inadvertently trap them inside. In North America, June, July, and August are the most likely times for young to be in the roost.
Should you have bats that need to be discouraged from roosting in an inconvenient location, there is no easy solution. Although bats in your attic probably pose little danger, and may in fact be a considerable benefit in control of noxious insects, sometimes the accumulation of guano or the presence of odors makes it desirable to discourage them. The only effective means of doing this is to build them out, closing all entrances and exits and plugging all small holes that might allow access to the space (see How Can Bat Problems Be Avoided?).
To date all electronic and chemical means have been ineffective in repelling bats. This includes all the common chemicals commercial pest-control firms will offer to pump into your location. Such a cure is likely to be far more harmful to you than to the bats. Ultrasonic devices designed to interfere with bats’ echolocation system have proved equally ineffective.
Lights or fans in a few particular situations have had limited success. These relatively innocuous methods can be tried with little likelihood of harmful side effects, but their chances of long-term success may not be great. Similarly, short-term results may be possible with commercial spray products designed to keep pets off furniture. Also, exclusion is often relatively easy, safe, and permanent.
Many people now recognize the importance of maintaining active bat colonies nearby and are constructing a variety of artificial roosts in order to attract bats (Figure 3.1). Bat houses are becoming increasingly popular and may provide an excellent way to attract bats without having to share your own house with them. Although bat houses have been used in Europe for decades, they have only recently become common in the United States, and little is known about how to maximize their effectiveness (Figure 3.2).
One valuable contribution available from Bat Conservation International is The Bat House Builder’s Handbook, by Merlin D. Tuttle and Donna L. Hensley. This booklet contains a wealth of background on the importance and value of bat houses as well as practical information on how to build them, where to site them, and other secrets to successful occupation of bat houses by various species.
Figure 3.1. A bat house mounted on a pole near Safford, Arizona.
Figure 3.2. A successfully occupied bat house for little brown bats, Myotis lucifugus, near State College, Pennsylvania.
Bat Conservation International is currently conducting a research project on bat house use with volunteers in 49 states, several Canadian provinces, and some additional countries. Volunteers gather data on standardized forms to report to the central database in Austin, Texas. Anyone wishing to participate in this project can write for further information to North American Bat House Research Project, Bat Conservation International, P.O. Box 162603, Austin, Texas 78716.
A sick bat should be left strictly alone. Call your local animal control office to deal with the animal. If you have to remove such an animal from the house, use thick gloves and make sure the bat is placed where it will not be found by pets or other animals. Bats that are flying normally are unlikely to be sick, but animals that are on the ground or unable to fly should be assumed to be sick and treated with caution.
It is probably unfair to say that most people dislike bats nowadays. Although bats certainly have suffered from myths, legends, and bad press over the years, the negative attitudes toward them seem to be turning around recently. As people become better educated about bats, their attitudes change from either indifference or actual dislike to interest, wonder, and even appreciation.
The early associations of bats with darkness and evil were certainly unwarranted. In addition, the occasional incidence of rabies in bats led to a sense of distrust that has also proved unfounded. As educational programs continue and our knowledge of the valuable services bats provide all over the world increases, the outlook for their protection and continued contributions is improving.
Figure 3.3. A stylized bat on a red mat at a Q’ing dynasty Buddhist shrine.
Certainly bats are not disliked or mistrusted in all cultures. In China, for instance, bats are considered good luck, and a stylized bat symbol is used as a good luck charm (Figure 3.3). In North America, Navajo culture considers bats mentors of the night and identifies them with a prominent deity, Talking God.
Playing a prominent role in a culture does not, however, always ensure ideal treatment for bats. The Chamorro people, native to the island of Guam and the Northern Mariannas, consider fruit bats important to their culture and celebrate that link by eating them as ceremonial dishes on traditional feast days. As a result fruit bats have become very scarce on those islands; they have even been imported from other island groups to satisfy the culturally based market.
Gary McCracken, a professor at the University of Tennessee who studies bats, has assembled a considerable amount of information on them for The Encyclopedia of American Folklore and Superstition, and he also summarized that information in a series of six articles in Bats, the quarterly publication of Bat Conservation International. He concludes that bats are frequently seen as liminal animals, which means that they do not fit into people’s view of the normal scheme of things. They tend to be in between and thus difficult for people to identify with. For instance, people frequently are not sure whether bats are mammals or birds.
North American Indian tribes have a variety of myths and legends about bats. One has bats being created by birds to help them win a ball game with the animals. This legend also accounts for the origin of the flying squirrel in much the same fashion.
There are variations on the ambivalent quality of bats from many cultures. On the Pacific islands of Samoa and Fiji, legends have bats originating by stealing the wings of birds. One variant of this legend reverses the roles: flying foxes originally walked on all fours and rats had wings. The bats borrowed the rats’ wings and never returned them, causing lasting enmity, as one might well imagine. This is the reason rats climb trees and try to eat young bats.
One especially engaging legend comes from the Pomo Indians of California. Their myth suggests a bat that can eat obsidian and spit out arrowheads. In fact, there is a bat called the California leaf-nosed bat, Macrotus californicus, that has an arrowhead-shaped nose leaf (see photo F in the gallery). Scholars speculate that this distinctive-looking feature led to the legend of the arrowhead-producing bat.
Figure 3.4. Southeastern myotis, Myotis austroriparius, and endangered gray bats, Myotis grisescens, returning at dawn to their nursery roost in Judges Cave, Florida. This cave is now a protected bat sanctuary.
This is frequently the first question asked when one tries to make the case for bat conservation. Fortunately, it is also an easy question to answer because the value of bats is obvious once one understands a bit about their biology.
For temperate zone bats, the main value is insect control. These little insectivores put away enormous quantities of insects every summer night, all over the northern and southern hemispheres (Figure 3.4). Having a bat house instead of an electronic bug zapper in your backyard makes for far more pleasant cookouts. Bats’ efforts at pest control are also a boon for orchardists and farmers. In addition, the guano that bats produce is a valuable fertilizer, in both natural ecosystems and agricultural systems (Figure 3.5).
These insectivores have the added benefit of serving as indicators of the health of the ecosystem. The free-tailed bat declines of the 1960s were a wake-up call to the dangers of long-lived pesticides in the environment. Such pollution signals are going to be increasingly important in our world of ever-expanding human populations and economic development.
Figure 3.5. A cave in Thailand that contains approximately 500,000 wrinkle-lipped free-tailed bats, Chaerephon plicata, which are important sources of guano for fertilizer. Annual sales of guano from single caves amount to more than $50,000 (US) and often are a major source of income for local villages. Huge bat colonies such as this consume many thousands of kilograms of insects nightly. Bats in nearby caves are now largely extinct as a result of overharvesting for human food. To protect these bats, the owner pays a guard to spend each night at the cave.
In the tropics bats are even more valuable to the functioning of natural and agricultural environments (Figure 3.6). They serve as pollinators and seed dispersal agents for hundreds, and probably thousands, of species of tropical plants (Figure 3.7). Many plants have adapted to the benefits of this service by opening flowers and producing nectar only at night to attract the bats (Figure 3.8). Others produce fruits whose seeds are distributed well away from the parent plants by flying bats (Figure 3.9).
These ecosystem services are vitally important to virtually every major habitat type on earth. Bats are missing only from polar ecosystems and a few small, remote oceanic islands. The loss of significant numbers of species of bats would have far-reaching consequences for the other animals and the plants that share their communities.
Figure 3.6. (left) A short-nosed fruit bat, Cynopterus sphinx, eagerly licking the nectar reward from a wild banana flower. The bat’s face will soon become covered with pollen, which it will carry to the next plant, thereby ensuring that the plant will bear fruit and continue the cycle. Even though cultivated bananas are vegetatively reproduced on plantations, bat pollination is critical to the survival of genetic strains of wild progenitors that could someday prove essential to the development of new, more productive, or disease-resistant varieties.
Figure 3.7. (right) A big fruit bat, Artibeus lituratus, pollinating a flower of the neotropical tree Pseudobombax. This flower opens at dusk and falls off by morning. Like many bat-dependent flowers, it is white, enabling bats to see it more easily on dark nights.
Figure 3.8. A Wahlberg’s epauletted fruit bat, Epomophorus wahlbergi, (left) coming to a baobab flower to feed, (right) its body collecting and distributing pollen in the process. Like many plants that depend on bats for reproduction, the baobab has blossoms that are lightly colored and scented, and thus easier for nocturnal feeders to find.
Figure 3.9. A southern long-nosed bat, Leptonycteris curasoae, approaching a cardon cactus fruit. Eating in flight, the bat repays the cactus for the luscious midnight snack by dispersing its seeds. In the spring, as lesser long-nosed bats begin their northward migration from southern Mexico, they feed on the nectar from flowers of the saguaro, organ-pipe, and cardon cacti. During many nights of feeding, the cacti are inadvertently pollinated as the bats probe the flowers for their sweet treat. Later in the season the pollinated flowers develop into rich fruits, laden with thousands of seeds. As more bats pass through the area in June, they perform another service by eating the ripe fruits and dispersing the seeds. This bat species is thus essential to some of the Sonoran Desert’s most important plants, and the fact that the bats’ numbers appear to be declining raises concern for the entire ecosystem.
Recent advances in pharmacological studies have suggested potentially valuable uses for the anticoagulant compounds found in vampire bats’ saliva. Prospecting for new drugs is an important growth industry in many parts of the developing world, and finding such a potentially valuable resource in an animal that has been severely persecuted as a pest is an interesting object lesson in why we should protect all our natural resources.
Beyond all these practical reasons for protecting a valuable resource, bats are part of our natural heritage, to be enjoyed for purely aesthetic reasons. Furthermore, surely these remarkable products of millions of years of evolution have every right to exist for their own sake, regardless of any value system imposed by humans.
Studying bats is a rewarding career, especially for people with an abiding curiosity about the natural world and its inhabitants. Bat biologists enter the field from a variety of disciplines, but the majority are mammalogists. Mammalogy is the discipline of zoology devoted to studying mammals, and bats are one of the most diverse and poorly known groups of mammals.
Other bat biologists are interested in particular systems; for instance, neurobiologists are frequently interested in echolocation. Echolocation is uncommon among animals, and the principles learned from the study of bats are invaluable to studies of the physics of sound transmission and the processing of sounds in animal brains. Physiologists interested in the functioning of various systems in animals and in humans study bats as unique examples of flying mammals and of animals that spend a considerable part of their lives upside down, requiring interesting adaptations in the circulatory system, among other things.
However one reaches the goal of studying bats as a profession, the first step is to obtain a good undergraduate education in biology. Although it is not possible to specialize in mammalogy as an undergraduate, it is possible to take courses in mammalogy, field biology, and at some universities even special seminars in bat biology. Courses in ecology, behavior, botany, and entomology will also provide good background. Other biological subjects that will be useful include genetics, physiology, comparative anatomy, systematics, and techniques of molecular biology. Depending on your future specialty, additional courses in foreign languages (much of the scientific literature is in languages such as German, French, Russian, Japanese, and Chinese, and fieldwork in Latin America requires Spanish and Portuguese), statistics and other areas of mathematics, and computer techniques will be very useful.
The next step is to choose a graduate school. Contacts made through your undergraduate professors will assist in this process. If you know that you are going to specialize in mammalogy, ecology, or behavior, you should select a school with a mammalogist, vertebrate zoologist, or behaviorist on staff. If you definitely intend to work on bats, it makes sense to choose someone who also specializes in them. This will ensure not only that you get the proper mentoring from your major professor but that you will be part of a cadre of graduate students with common interests to assist in your education.
There are many universities with good graduate programs in mammalogy, ecology, or behavior, both in the United States and abroad. Additional information on careers in mammalogy can be obtained by contacting the American Society of Mammalogists, the major professional organization for people in this discipline. The society welcomes student members, and information on becoming a member can be obtained by writing the secretary-treasurer, listed on the inside covers of issues of the Journal of Mammalogy.
Figure 3.10. A bat biologist showing a red bat, Lasiurus borealis, at a Bat Conservation International workshop in Pennsylvania.
With a little diligence you can also discover if there is a bat biologist in your area. Looking at articles in the Journal of Mammalogy, or at the bibliographies of this and other books and articles about bats, will give you names of bat biologists and some idea of their professional interests. Volunteering your services at a local university, museum, or zoo where bat studies are going on can be a rewarding way to enter the field and gain valuable experience.
Today you can find bat biologists employed by a wide variety of governmental and private organizations. Universities provide a major source of employment, but many bat biologists also work for museums and zoological parks. In addition, federal agencies—such as the U.S. Fish and Wildlife Service, the National Park Service, the Forest Service, and the U.S. Geological Survey—employ bat biologists. Also many private environmental organizations and consulting firms offer employment opportunities (Figure 3.10).
Bat biologists use a variety of methods to catch bats in order to study them. We actually knew very little about bat natural history until about a half century ago, when Japanese mist nets came into use for capturing bats. These very fine nets, almost like hair nets, are about 2 meters high and range from about 5 to 30 meters long. They can be strung across flyways, such as paths in a forest, or over water sources, such as ponds and creeks, to catch bats as they fly along. The bats hit the nets and become entangled in them without suffering injury (Figure 3.11). They can then be removed carefully and either marked and released for later recapture or taken to the laboratory for further study (Figure 3.12).
Figure 3.11. (left) A spotted bat, Euderma maculatum, entangled in a mist net. Figure 3.12. (right) A bat biologist removing a big brown bat, Eptesicus fuscus, from a mist net.
Variations on this theme have been developed more recently. Denny Constantine, a veterinary biologist who has contributed greatly to our knowledge of bats and diseases, developed a type of funnel trap to use in the openings of large caves; it catches the bats as they exit (Figure 3.13). Merlin Tuttle refined this device, and his smaller version has become known as the Tuttle trap. Basically, it consists of two parallel rows of monofilament line strung vertically between metal frames. The bats hit the lines and slide down into a plastic catch bag, where plastic flaps keep them from escaping. These traps are portable and easy to hoist into cave entrances or into the forest canopy as needed.
Bat biology has come a long way in the last couple of centuries and has grown very rapidly in the last couple of decades. We now understand much more about the biology of bats in all areas than we did in the 1960s, when my own interest in bats began. The advances in understanding sophisticated systems such as echolocation have been particularly noteworthy.
Nevertheless, we have a considerable amount to learn about this important and interesting group of animals. Much of our knowledge about bat biology comes from a relatively few species (Figure 3.14). With over 925 species to choose from, there are still many bats that are almost completely unknown (Figure 3.15). Even the basic classification of bats is little more than the most recent version of a phylogenetic hypothesis, which undergoes adjustment with each new study that is published.
Figure 3.13. Constantine and Tuttle traps can be used to catch gray bats (Myotis grisescens) as they emerge from this cave in Tennessee.
Figure 3.14. The southern long-nosed bat, Leptonycteris curasoae, in flight to a cardon cactus flower. This is one species that has become much better known recently, thanks to several years of hard work by a dedicated team of bat biologists.
Figure 3.15. An Underwood’s long-tongued bat, Hylonycteris underwoodi, a relatively common yet quite poorly known species of nectar-feeding bat widely distributed in Latin America.
Our knowledge of the interactions of bats with their environment is of critical importance to conservation biology (Figure 3.16), an area that is going to grow considerably in the early twenty-first century. Students interested in bat ecology and behavior will have ample opportunity to contribute to the field (Figure 3.17), especially in tropical regions, where the bulk of bat diversity is concentrated and where we understand the least about the world’s most complicated ecosystems (Figure 3.18).
Figure 3.16. A Commissaris’s nectar bat, Glossophaga commissarisi, another widespread but poorly known species, whose interactions with the environment play an important but as yet largely undocumented role in the functioning of tropical ecosystems.
Figure 3.17. A black flying fox, Pteropus alecto, seen here pollinating a bottle brush flower. This bat is an example from the Old World of a worthy subject for the study of bat ecology.
Figure 3.18. White fruit bats, Ectophylla alba. Spectacular tropical bats such as these will attract the attention of future students of bat biology.
There are several sources of information on all these topics. The references in the bibliographies contain a wealth of information on every aspect of bat biology. Your local library should have at least a sampling of them.
There are also organizations devoted to correcting misinformation about bats. The oldest and largest of these is Bat Conservation International, in Austin, Texas. This is a nonprofit membership organization formed to document and publicize the value and conservation needs of bats, to promote conservation and research projects, and to assist with management objectives worldwide. For additional information write: Bat Conservation International, P.O. Box 162603, Austin, Texas 78716.
Some bat conservation groups in other countries include the following:
Australia
Australasian Bat Society
Lawrie Conole, Newsletter Editor
2/45 Virginia Street
Newton 3220, Victoria, Australia
phone 03-9-669-9732
fax 9-663-3669
e-mail (lconole@mov.vic.gov.au)
Canada
Bat Conservation Society of Canada
P.O. Box 56042, Airways Postal Outlet
Calgary, Alberta T2E 8K5, Canada
phone 403-860-BATS
e-mail (BCSC@cadivision.com)
England
The Bat Conservation Trust
Colin Catto, Scientific Officer
15 Cloisters House
8 Battersea Park Road
London SW8 4BG, England
phone 0171-627-2629
fax 0171-627-2628
e-mail (batcontrust@gn.apc.org)
Germany
AG-Fledermausschutz BaWue
Universität Tübingen
Auf der Morgenstelle 28
72076 Tübingen, Germany
Koordinationsgruppe
Fledermausschutz in Deutschland
K. Richarz, Chairman
Staatliche Vogelschutzwarte
Steinauer Strasse 44
D-60386 Frankfurt, Germany
phone 0049-69-411532
fax 0049-69-425152
Naturschutzbund Deutschland
BAG Fledermausschutz
Dr. J. Haensel
Hauptstrasse 13
D-13055 Berlin, Germany
Greece
Hellenic Bat Society
P.O. Box 3277
Gr-102 10 Athens, Greece
phone/fax 301-330-2548
The Netherlands
Vleermuiswerkgroep Nederland, VLEN
Emmalaan 41
NL 3581 HP Utrecht, The Netherlands
phone/fax 030-2544642
South Africa
Bat Interest Group
c/o Dr. Peter Taylor
Durban Natural Science Museum
P.O. Box 4085
Durban 4000, South Africa
phone 31-300-6218
fax 31-300-6302
Bat Conservation Switzerland
Fledermausschutz SSF/KOF
Zoological Museum of the University
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
phone 01-2574776
fax 01-364-0295
e-mail (nyct240@zoolmus.unizh.ch)
Centre de coordination ouest
pour l’étude et la protection des
chauves-souris
Muséum de l’histoire naturelle
Case postale 6434
CH-1211 Geneva 6, Switzerland
phone 022-735-9130
fax 022-735-3445
e-mail (moeschl@mail.ville-ge.ch)
In addition, there is an e-mail discussion list called “Batline,” which can be reached at batline@unmvma.unm.edu.
