Bat Facts II
October 25th, 2022 by georgann
Chances are you know and believe more myths and superstitions than facts about bats. And chances are that if you ever saw one up close, you would be either totally repulsed or truly fascinated. That’s just the way bats are; so ugly that they are cute. The truth is, bats are not only interesting animals, but also extremely beneficial. The best way to get to know and love bats is to dispel the many myths we believe about them.
MYTH: Bats are just ugly, little, hairy birds.
FACT: Bats are not birds, but mammals–they are covered with hair, give birth to live young, and nurse them as other mammals do. Although bats have mouse-like faces, they are not related to rodents, but are in their own order, Chiroptera, which means “hand-wing”. They are then subdivided into two sub-orders. The Megachiroptera, or “flying foxes” are found in the Old World tropics. The Microchiroptera comprise the other bats–approximately 1,000 species found worldwide.
Bats occupy just about every habitat except extreme desert and polar biomes. Evolving nearly 50 millions years ago, they display an interesting variety of sizes and appearances. The smallest bat, the bumblebee bat of Thailand, weighs less than a penny, while the Old World flying foxes have wingspans of up to six feet and weigh two pounds. Bats range in color from jet black to red, yellow, or white. Many have large ears and eyes. Some have small, mouse-like ears and tiny eyes. A few bats appear comical with enormous ears, nose leafs, chin-leafs, and other bizarre facial features.
There are 42 species of bats that live in the United States and Canada. The more common bats in Georgia include the big brown bat, (Eptesicus fuscus), evening bat (Nycticeius humeralis), eastern pipistrelle (Pipstrellus subflavus), Mexican free-tailed bat (Tadarida brasiliensis), red bat (Lasiurus borealis), hoary bat (L. cinereus), northern yellow bat (L. intermedius), silver-haired bat (Lasionycteris noctivagans), southeastern bat (Myotis austroriparius), eastern long-eared bat (M. septentrionalis).
MYTH: Bats are blind.
FACT: Bats may, indeed, have small eyes, but they are certainly not blind. Many have excellent vision. However, bats communicate and navigate with high-frequency sounds. Their echolocation system is thought to be billions of times more efficient than any similar system developed by humans. The high-frequency sounds that a bat emits bounce back to its ears, enabling it to detect objects as fine as a human hair in total darkness. The strange-looking nose-leafs and chin-leafs probably function as structures to gather and focus these sound pulses.
MYTH: Bats suck your blood.
FACT: Wrong. Only vampire bats from tropical South America feed on blood drawn from cattle and horses. A few other species prey upon birds, mice, fish, frogs, and even other bats.
Seventy percent of all bat species use their sharp canines and molars to feed on insects. Bats are, in fact, the primary predator of night-flying insects and play a vital role in the food chain. Unlike electric bug-zappers and purple martins, bats actually do catch and eat mosquitoes. Each bat can consume up to 600 mosquitoes an hour. Bat biologist, John Whitaker, documented that a single colony of 150 bats can protect a farmer’s crop from 38,000 cucumber beetles, 16,000 stink bugs, 19,000 June bugs, 50,000 leafhoppers, and 18 million rootworm moths. Merlin Tuttle calculates that a colony of twenty million free-tailed bats living in Texas can consume 350,000 pounds of insects nightly.
Many tropical bats eat fruit, pollen, and nectar. Throughout the tropics the seed dispersal and pollination activities of fruit-and nectar-eating bats are vital to the survival of rain forest plants. Commercially grown products such as bananas, cashews, carob, and cloves rely on bat pollination for a productive harvest.
On the other end of the food factor is the contribution of bat droppings or guano. By bringing in food and leaving droppings, bats provide raw materials for a number of cave animals. The guano supports organisms that in turn become food for many unique and fascinating spiders, centipedes, salamanders, crayfish, and fish that live only in caves.
MYTH: All bats carry rabies.
FACT: It is a common misconception that all bats carry rabies. In truth, not even a lot of bats carry rabies. Twenty years of research has shown that only .5% of bats have rabies, a frequency rate not unlike that of other mammals. Rather than experiencing outbreaks of rabies, bats only occasionally become infected and then quickly die. The chances of being bitten by a bat and contracting rabies are far less than one would imagine. In fact, fewer than 25 Americans are believed to have contracted rabies from bats in the past fifty years.
The transmission of the rabies virus through the air is rare. Thousands of people have explored caves populated with bats and only two have contracted rabies. There is no evidence to support rabies infections from bats in your house or bat box.
One is much more likely to suffer from a histoplasmosis infection than rabies. Histoplasmosis (Histoplasma capsulatum) is a fungus found in soil that is enriched by bird and bat droppings. People are most likely exposed to large amounts of this fungus from chickens on poultry farms. Droppings from a large colony of bats roosting in a hot, dry attic may support the fungus. Their accumulated droppings should be carefully removed while wearing a respirator to avoid inhaling the fungus.
Although some people learn to live with bats in their house, they can be excluded from attics by finding their entry point and blocking their access with wood or screening. Be careful not to trap any bats in the house as they will die and rot.
MYTH: Bats nest in your hair.
FACT: No, no, no! Never. That bat flying erratically above you is hawking insects, not checking out your hairdo for roosting. And bats will not accidentally bump into your head. Remember the precision of echolocation?
During the months that insects are active, bats will roost in caves, mines, buildings, rock crevices, or trees during the day and emerge at dusk to feed. In more northern climates, bats will hibernate during the winter or migrate south to warmer areas, often flying considerable distances.
Although bats mate in the fall, many species of females can store sperm and fertilize their eggs in late winter or early spring. One to four babies, or pups, are born in the spring when the insects have emerged again. Pregnant and nursing females, often of mixed species, may cluster together in colonies.
MYTH: There is nothing I can do to help bats.
FACT: Bats are barometers of the environment. They act as indicators of environmental health. Their decline can be direct and quick–death by pesticides or more subtle–loss of roosting habitats. Cave exploration, or spelunking, is one of the most important causes of bats becoming endangered. In 1963, close to 30 million Mexican free-tailed bats lived in Eagle Creek Cave, Arizona. Since 1989, their numbers have been reduced to 30,000. Human activities including caving, poisoning, burning, and shooting have contributed to worldwide bat decline at an alarming rate.
What can we do? One solution is to find and use suitable alternatives to pesticides. The other is to encourage bats to nest in boxes. In the southeastern U.S., the big brown bat is the most likely species to occupy bat boxes. Other bats that may find a box attractive include the southeastern bat, eastern pipestrelle, and Mexican free-tailed.
PLACEMENT AND LOCATION OF YOUR BAT BOX
To be perfectly honest, establishing a bat colony in a bat box is not easy. Bats appear to be rather particular about box construction, placement, and location.
1. Go outside and watch bats flying around your yard and neighborhood. The presence of bats is a good indication that you may be able attract them to a bat box. Bats are most likely to be attracted to your box if there are insufficient natural roost sites and hibernating sites within migratory range. In other words, they are unlikely to move into a bat box unless it is needed.
Bats living in your attic can be evicted and, hopefully, may move into your bat box. However, it is just as likely that they will simply move into a neighbor’s attic!
If you don’t see any bats, you may not live close enough to a water source such as a stream, pond, or river or there may not be enough potential winter hibernating sites in nearby caves. You may not have enough insects in the area to sustain a colony. Having a night light close to your home may be one way to attract insects for bats.
2. Bats do not like to use a box that has a difficult approach and access. Mount your box at least 15 to 20 feet high on the side of a building or a tree away from branches. Often the best location is the highest point of your house. If you mount your box on a tree, shield it from cats and snakes by wrapping a sheet metal band two feet wide around the trunk.
3. Bats are temperature sensitive. Choose a well-built box that allows for even and constant temperature distribution. Some boxes are even insulated. It should contain at least two chambers with spacing at 7/8″ to l-l/2″ apart. The front of the box should have small air vents or holes near the top to allow hot air to escape. Your box should face south, southeast, or southwest to absorb the sun’s warmth in the winter months, yet be sheltered from direct sun in the summer. I may help to hang three or four boxes, each with a different exposure, providing a variety of temperatures for bats’ seasonal needs.
4. The inside surfaces of your box should be rough. Choose or make your box from rough-sided cedar. Some bat experts encourage covering each inside surface with hardware screening. Be sure to cover the edges of the screening so that the corners and cut wires will not harm the delicate feet and wings of the bats. You can use silicon cement to smooth over the edges. Some boxes have a landing pad with hardware screen extended below the entrance for bats to land upon.
5. It may take awhile for bats to find and move into your box. If bats have not found your box in two years, move it to another location. Also, keep in mind that a bat box may not be occupied everyday; some bats may use it only as a night roost or some only briefly during migration. Even if bats don’t use your bat box, it makes a great conversation piece and gives you a chance to talk about their importance to your neighbors.
For more information about bats:
Bat Conservation International, P.O. Box 162603, Austin, TX 78716
America’s Neighborhood Bats, Merlin D. Tuttle, Un. of Texas Press,1988.
“Bats in Fantasy and Fact”, Joshua Laerm, Georgia Wildlife Federation, Fall/Winter 1993
The World of Bats, Alvin Novick, Holt, Rinehart, 1969.
Bats of America, Roger Barbour, Univ. Press of Kentucky, 1969.
Just Bats, M. Brock Fenton, Univ. of Toronto, 1983.
Birding Adventures, Inc.
BUILDING A BAT BOX
Make your bat box carefully and you will increase your chances of attracting bats. Each piece should be glued and then fastened together so there is no air or water leaking into the living area. Line each inside surface with hardware cloth for easy gripping by young bats. Do not paint your box. Natural weathering is important to establish a colony of bats. Some bat experts advocate spreading bat guano on your new bat box to encourage bats to take up residence!
Materials: one 8′ piece of 1″ x 8″ untreated, rough-sided lumber
one 10′ piece of 1″ x 10″ untreated, rough-sided lumber for top
About 20 six-penny galvanized nails
saw, hammer, ruler, tape measure, pencil
Step 1. Cut the 8′ piece of rough lumber into six pieces
a) three pieces each 16″ long (2 sides and 1 back)
b) one piece 11-3/16″ long (front)
c) one piece 13″ (for partition c)
d) one piece 11″ (partition d)
Step 2. Cut a roof 10″ x 10″ from the 10′ piece of rough lumber.
Step 3. Line inside surfaces of the front, back, and chambers with
hardware screen and smooth their edges with silicone.
Step 4. Cut the tops of two 16″ pieces at an angle shown in figure 3.
One side of each piece should measure ll-3/16″.
Step 5. Take the third 16″ piece (the back) and cut one end at a 30 degree
Step 6. Repeat step 5 with the front piece, both partition pieces, and
the edges of the top piece.
Step 7. Begin building. Glue the edges of all pieces before nailing them
together. Take the two sides and nail them to the back.
Nail the front piece to the two sides completing your cube.
Line up each piece at the top to provide a tight seal for the
Step 8. Insert partitions. Position each partition no more than 1-l/2″
apart. The 13″ partition (c) lies closest to the back.
The 11″ partition (d) lies closest to the front.
Step 9. Glue and place the 10″ x 10″ piece on top so that the back edge
is flush with the box back and creates an overhang in
front and on the sides of the box.
Step 10. Use hangers or nails so that your box hangs solidly on the side of
a tree or building.
Step 11. If you chose to use a landing pad, nail it beneath the box. A
landing pad would be most useful if your box is hung from
a brick or stucco building.