Great Bats Alive: Myths vs. Reality
Stan Wojteczko, Chuck Drake – Moderators
Chicago Zoological Society/Brookfield Zoo
While holding a Rodriguez Fruit Bat named Newt, the Brookfield Zoo keeper at Australia House expounded during the daily “Keeper Chat”: People are afraid of bats. They don’t understand them and there are so many myths.” It’s true, and there are, because of this misunderstanding, a lot of visitors who “hightail” it through or do not even enter the Rodriguez Fruit Bat exhibit. They don’t know what they are missing!
Years ago after seeing the movie Dracula, my lady friend and I walked home, the whole way looking over our shoulders. She had a Bee Hive hair-do. I hoped nothing would land in her “do” and luckily nothing did. We didn’t talk all the way home; we just kept looking around nervously. This brings us to the topic of this presentation.
Common Myths and Misunderstandings
1. Bats are vampires in disguise. 2. Bats are flying rodents. 3. Bats are blind (“blind as a bat”). 4. All Bats eat blood like vampires. 5. Bats get into your hair. 6. Vampire bats attack people. 7. Vampires hang upside down to launch quicker at people, mammals and other creatures. 8. There are “bats in the belfry.” 9. Bats only live in tropical forests and caves. 10. Most bats carry
rabies. 11. Bats don’t taste very good and are not preyed upon by other animals. 12. Bats don’t contribute anything economically. 13. Bat populations are stable and their future is secure.
Reality about Bats
1. When you think of vampire bats, you think of man-sized vampires that live “deep in the Carpathian mountains in Transylvania.” But actually no vampire bats live in Europe. And the vampire bat is a mere three inches long, weighing only two ounces.
2. Bats (order Chiroptera) are among the most diverse and geographically dispersed kinds of living mammals. Rodents do not fly or roost in large groups; rodents have their own order, Rodentia…but flight is the main difference between the two.
3. Bats can see very well. Their eyes are specialized for functioning under conditions of low light because their retina consists almost entirely of rod cells. Their eyes are well adapted to find food, roosts, and each other. Eyesight is needed to help look for prey, not people, and some even have color vision.
Another form of sensing the environment is echolocation (“sound sensing”)
which allows bats to “see” by sound. They send out sound waves and listen for returning echoes.
Although echolocation is used to detect obstacles and roost sights, it is used primarily by insectivorous bats hunting for dinner.
4. Bats don’t just drink blood. “They eat a wide assortment of fruits, vegetables, insects, flowers, nectar, pollen, fish and other vertebrates, and some blood (vampire bats). In fact, sweet potatoes, which they suck the juice out of, are a favorite of the Rodriguez Fruit Bat here at Brookfield Zoo. Bats have different primary food sources; insects are the diet for over 500 species of bats. Fruit is the diet for approximately another 300 species. Some bats feed on nectar and pollen; a few species are the primary pollinators of some plants. There are bats that are carnivorous, eating small mammals, including other bats, birds, lizards, frogs, etc. A few species catch and eat fish like the Bulldog bat of South America. Some species in the Genus Myotis, which are found in Illinois, can eat up to 600 mosquitoes in one hour.
Large colonies of free-tailed bats eat up to a half-million pounds of insects in one night. A half-million pounds would be about the size of 38 adult male African elephants!
There are only three species of blood-eating bats (vampires) in the world. They are all native to the New World tropics and subtropics. The white-winged (Diaemus youngi) and the hairy-legged (Diphylla ecaudata) are primarily restricted to areas of intact forest where they feed on the blood of birds, reptiles, and other forest animals. The third species of vampire bat, the most
well known, is the Common Vampire (Desmodus rotundus) which thrives in agricultural areas and feeds mostly on cattle, pigs, and chickens. In coastal regions, these vampires sometimes feed on sleeping sea lions. They crawl up to the animal, puncturing the skin between the webbed flippers, and drink up the blood using their grooved tongue like a straw! Only a small amount of blood (two or three ounces) is taken and the sea lion is not harmed. We’ll have more about these vampires later! You can observe a re-enactment of this at our Living Coast Exhibit, adjacent to the Humboldt Penguins. If you look close you may also see a couple of live Vampires behind the glass there.
5. Bats are afraid of people and try to avoid them. They do not intentionally get tangled up in peoples’ hair. In fact, cave dwelling bats get spooked at the slightest disturbance which causes them to fly around crazily! They appear to be the ones who are scared. As Dr. Gary McCracken noted in an article in Bat Conservation International, “Certainly there are occasions when this happens, but hardly enough to explain the profusion of myths. While working in a large cave colony in Texas, I’ve had bats in my hair, as well as up my pants leg, and just about everywhere else. But that’s to be expected in a large disturbed roost.” Most stories about bats getting into hair originate from normal bat behavior. Bats frequently fly low over the heads of people who are walking or sitting outside in the evening. Foraging bats often swoop over people’s heads at
night, but they are in search of insect prey, not hair entanglement. The rapid, seemingly erratic movements of echolocating bats who are also making avoidance moves in hot pursuit of insects, often cause people to think they are being attacked.
6. The Common Vampire bat, Desmodus Rotundun, the only bat species to feed mostly on the blood of mammals, is found in both the tropics and subtropics; they are not found in the United States. Sometimes in order to survive bats must turn to humans as a life source. Common Vampire bats normally feed on cattle, horses, goats and pigs, but if this livestock is sold off to market or is abruptly removed, bats need to feed on the next available warm-blooded animal.
Vampire bats need to drink their weight in blood every two days or they will die. Humans, especially those who are sleeping in areas unprotected by houses or tents, have at times become the vampire bat’s food source. In addition, logging, gold mining, and deforestation have forced bats out of their regular habitats, resulting in having to find their food source near or within human developments. According to recent news reports, bats in Nicaragua, northern
Brazil, and Peru have “attacked” people, but only in order to survive.
Unfortunately, the deadly virus, rabies, is also transmitted through the vampire bat’s feeding, which, if untreated leads to death. But- this all takes place in the tropical areas named above and not in the US or anywhere in North America; there is nothing to fear to prompt “a wipe them out strategy or mindset.”
7. Bats hang upside down because they cannot stand. Like birds, bats have lost density in their bones, reducing body weight, to make flight easier. There is more strength in tension than in compression which is why bats legs are strong enough to let them hang but not to stand like most animals. Because of special adaptations, the blood does not rush to its head. They have another feature pertaining to flight: the hind limbs of bats are unique among mammals in being able to rotate 180 degrees allowing the knees to point backward. This facilitates steering during flight and the head-down roosting posture. Some bat species are capable of walking on the ground; these include both the Rodriguez Fruit and Vampire bats.
8. True! There just could be “Bats in the Belfry!” It’s high, dark, possibly humid, cozy, and protected, especially in the countryside. Who knows? Maybe they are getting a kick out of a free ride on the bells. There once was another definition which implied a person was having crazy thoughts in the head coming from erratically flying mammals flying inside of the head – impossible! But if someone says he’s got bats in his belfry, you know what they’re thinking.
9. The world is home to 1,100 species of bats, the second largest group of mammals after rodents, and the only mammals that fly! There are 42 species of bats in the US and 68 species of bats in Australia. They are a realtor’s dream because they are at home on all continents except Antarctica, are found from the southern tip of South America to northern Scandinavia and are not especially picky. They are absent only from the Polar Regions and a few isolated oceanic islands. Roosting habitats include foliage, caves, rock crevices, hollow trees, crevices beneath exfoliating bark, and an assortment of manmade structures both intended (bat houses) and unintended (attics/porches). Big Brown bats have a strong penchant for buildings; Little Brown bats like attics.
10. Out of the 1,100 species only one-half of one percent carries rabies. People are more likely to encounter a raccoon or a skunk with rabies than a bat. However those bats that are rabid, especially vampires, must be removed from the population.
11. You won’t catch me eating one, but bats are a staple in East Asia and the Pacific. In Nigeria bats are occasionally found in juju stalls because they are thought to cure barrenness. Juju stalls are markets that trade in animals (birds, bats, etc.) used in micro-medicinal practices and fetishes in Sub-Saharan Africa. In some areas, such as the Marianas in the western Pacific, fruit bats are considered a delicacy and are served at social occasions such as village fiestas, weddings, christenings, and holiday celebrations. In many local markets bats have a considerable commercial value. In northern Sulawesi up to 16 species of bats were found to be available in local markets. Fruit bats are a luxury item on restaurant menus in the Seychelles. Restaurants advertise bat curry, and it was estimated that one restaurant could use up to 1,500 bats a year.
Bats are also eaten by many other animals. They are preyed upon by birds, reptiles, and other mammals including other bats.
12. Hold onto your hats! Bats contribute to the environment and economy several other ways. Bats are important pollinators and seed dispensers in tropical forests throughout the world and have shared a long evolutionary history with angiosperms. Megachiptivan bat fossils have been found in ancient rain forests and are estimated to have inhabited these forests 35 million years ago.
In the Philippines bats have been credited with increasing the germination rate of fig seeds. On many oceanic islands fruit bats are the only animal capable of carrying large fruit and are considered “keystone species” as significant declines in forest regeneration rates and diversity would accompany their extinction. Many Pacific plants have become exclusively dependent on fruit bats for successful pollination. In Samoa during the dry season 80-100% of the seeds deposited on the ground (seed rain) are transported by fruit bats.
Bats appear to be the major pollinators of the cardon and the pipe organ in the Sonoran desert. Old World bats pollinate the valuable Baobob tree in Africa. About 200 paleotropical plants utilized by flying foxes (large fruit eating bats) provide medicines, food dyes, fiber, ornamental plants and timber. Pterodids are the primary pollinators of two plants extremely important to local economies of Southeast Asia: Durian and Petai. Bats play a role in both pollination and seed dispersals of a number of valuable timber species.
At least 440 useful products derive from about 160 plants that rely on bats’ pollination and seed dispersal. These products include timber, fruits, fiber and tannins worldwide, and to a lesser degree medicines and food items important to local markets. The durian fruit, Petai and Duku contribute $4 million annually to the Indonesian economy. Annual sales of Petai are expected to exceed $1 million in Peninsular Malaysia alone. Twelve tree species dependent on bats for dispersal are major timber species for Malaysia, one of the largest timber exporters in the world.
The kapok or silk-cotton tree, the fiber, bark and seeds of which are economically important, is pollinated by a number of bat species in Africa and South America. In the US, there is great news on the medical front. Scientists have learned there is an anti-coagulant in the saliva of vampire bats. Biomedical researchers have developed anti-clogging drugs to help stroke victims.
13. To conclude, while we appreciate their importance, bat populations appear to be declining everywhere, and several have become extinct or endangered; habitat loss due to deforestation is the main reason. On some islands bat populations have been disseminated by tropical storms. Closer to home, bats are under a lot of pressure these days. Widely misunderstood and misinterpreted, they have no intention of harming us. A mysterious new illness called white-nose syndrome has been killing large colonies of hibernating bats in the Northeast, and it is spreading fast. In the past four years, an estimated 1 million or more bats of six species have died.
Cave dwelling species are also at high risk. The decline results from hunting and vandalism. It could even include government eradication programs, such as in Mexico, Central and South America. Extensive use of pesticides and overgrazing of grasslands are increasingly important in population loss. Contamination and altering of feeding habitats; siltation of rivers and lakes from agricultural runoff; channeling of rivers for flood control; and clearing of riparian and hedgerow habitat are disrupting bat populations worldwide. Environmental contamination from pesticides and pollutants has been implicated in the decline of some North American species. The Indiana bat and the Grey bat, both found in Illinois, are on Federal and State endangered
species list. It is possible to reverse current population trends and ensure long term viability for many species. Limiting hunting and deforestation are critical components to ensure roosting and viable living spaces. Bat populations will not be secure until their ecological importance is acknowledged, their habitat requirements understood, and the protection of roosting sites and foraging areas is incorporated into land management policies. We need to drive the stake into Dracula’s heart and rethink our perception of bats! Many concerned citizens have erected bat houses on their properties increasing roosting opportunities.
Another way to change public perception is for zoos to install “myth” signs at the entrance to their bat exhibit, denigrating the effect myths have. That sign should include a picture of a gentle, soft bat like the Rodriguez Fruit bat that doesn’t have the typical scary bat face. Just looking at Rodriguez Fruit Bat right side up has been known to help overcome fear of bats. Please go enjoy the 35 Rodriguez Fruit Bats in their free fly zone in our Australia House. A cyclone hitting Rodriguez Island near Madagascar critically endangered the population, almost leaving it extinct. The species is still endangered with an estimated 1,000 in the wild population (from as low as 70). Although captive Rodriguez Fruit Bats are not being reintroduced into the wild, the captive population is a safety net for the species and serves as a model for conservation programs for other bat species. It is covered under the Species Survival Plan. Brookfield Zoo has been a major breeding and transfer institution for Rodriguez Fruit bats in captivity which number about 230 today. The North American population of the species was founded on just 71 animals imported to six U.S. institutions between 1987and 1994 from captive colonies in Jersey and Mauritius.
Another Brookfield Zoo species is the Vampire bat of Central America housed in our Living Coast exhibit because that is where they call home. There is a statue of one feeding on a sea lion’s flipper as well as live ones. Despite their fierce reputation, how we feed and care for these delicate creatures is key to their survival, and very interesting.
-Vampire bats are fed two times per day with bovine blood. (No cows are hurt in the process.) -In the a.m. a vitamin called Poly-vi-sol is added for iron addition (2 drops per food pan or 4 drops total).
-Optimum temperature range should be between 72-82 degrees
-Optimum humidity should be between 40-60 percent
-Light cycle: Should always have two night lights (2-60 watt bulbs) provided. In addition, lights are turned on for servicing and then turned back off afterwards. Many upside down plant holders are provided for roosting with plastic, lightweight mesh cable tied into the pot for climbing and hanging onto in the holding room. Many locations are offered to dissuade conflicts over territory. On exhibit, picket areas are recessed or curved in so that exhibit bats may prosper and feel secure.
-Water is provided around the clock even though it is undetermined how often they typically drink.
-Keepers hose and scrub daily.
Finally there is the Big Brown bat in our Swamp exhibit. The Big Brown bat is actually common to many habitats. Big Brown bats often live in dead trees, bat houses, old buildings and attics, and are found in the Chicago metro area. Big Brown bats roost in buildings in the winter in order to hibernate safely. They are the most closely associated with humans because of their year-round use of buildings. They are also highly beneficial to humans because they consume
extremely high numbers of insects, yet their population decreases every year from people killing them and their loss of habitat.
We offer the following websites as follow up to this discussion:
www.batconservation.org or www.batcon.org
Sources: Keeper Chat Bat Talk” Australia House, Brookfield Zoo
Frank J. Bonaccorso, “Bats of New Guinea”
Simon P Mickleburgh, Anthony M. Hutson and Paul A. Racey,
“Old World Fruit Bats, An Action Plan for their Conservation”
Ronald M. Nowak, “ Walker’s Bats of the World”