Frequently Asked Questions About Bats
Are bats related to birds?
Bats and birds both can fly, yet they developed this ability independently. They belong to different animal classes; birds are in a class called Aves while bats are in the class Mammalia. Bats are mammals, just like humans, which means that all bats are warm‐blooded, have hair, bear live young, and feed their babies milk.
How do bats move around in the dark?
All bats can see, but some use a special sonar system called echolocation. These bats make high frequency calls either out of their mouths or noses and then listen for echos to bounce from the objects in front of them. They are able to form pictures in their brains by listening to reflected sounds just like we form pictures
in our brains by interpreting reflected light with our eyes. In this way, bats are able to comfortably move around at night, avoiding predators, maneuvering around obstacles, locating their food, and capturing insects in total darkness.
Why do bats hang upside down?
Unlike the bodies of other animals, a bat’s body is best adapted for hanging upside down. Its hind limbs have rotated 180 degrees so that its knees face backwards. This rotation aids in the bat’s ability to navigate in flight and to hang by its feet. Bats actually have specialized tendons that hold their toes in place so that they are able to cling to their roosts without expending any energy. In fact, bats must flex their muscles in order to let go of the roosting surface. These adaptations are quite helpful for a flying mammal since bats only need to let go of the roost in order to drop into flight. Hanging upside down also provides bats with roosting space away from predators in safe places on the ceilings of caves, in trees, and buildings that few other animals can use because they have not evolved to hang upside down by their feet.
What do bats eat?
There are over 1,100 different species of bats in the world, living on every continent except Antarctica. Each one has developed special adaptations for how it lives and what it eats. For example, 70% of all the bats in the world eat insects and many of them use echolocation in order to find food and move around in the dark. Many small insectivorous bats can eat more than 1,000 mosquito‐sized insect in one hour. These bats are able to eat so much because they have high metabolisms and expend lots of energy in flight. Frugivorous bats living in tropical climates have very good eyesight and sense of smell for finding ripe fruit to eat. In the desert, there are nectar‐feeding bats which have long noses and tongues for harvesting nectar from flowers, as well as special enzymes for digesting the high‐protein pollen that accumulates on their faces. Carnivorous bats have sharp claws and teeth for catching small vertebrates such as fish, frogs, birds, or rodents. A few Latin American bats, the vampires, eat only blood.
How do vampire bats suck blood?
Vampire bats do not actually suck blood. They lap it up like a dog drinking water from a bowl. To begin feeding, the bat first must prick the animal with its two large front teeth, often in the foot or leg of a sleeping mammal or bird. An anticoagulant in the vampire’s saliva causes the blood to flow without clotting, allowing the bat to lick up its nutritious, protein‐filled diet. Vampires take only 2 tablespoons of blood while the host animal continues to sleep. There are just three species of vampire bats in the world and they all live in Latin America. They are very gentle creatures and will adopt orphans and regurgitate and share food for a member of the colony who could not find a meal the night before. The anticoagulant from these bats’ saliva has been synthesized and is now used in medication for human heart patients, showing that even vampire bats can be helpful to humans. However, when these bats feed on livestock, they can spread diseases and must be controlled.
How do scientists study bats?
Just like scientists who put radio collars on wolves and dolphins, bat biologists also radio‐tag bats using exceptionally small transmitters specially designed to be carried by bats. Once the bat has been tagged, researchers are able to follow it while it forages and returns to its roost. Scientists also use sophisticated night‐vision equipment, similar to that used by the military, in order to spy on night‐flying bats without disturbing them. Researchers can eavesdrop on bat echolocation calls by using ʺbat detectorsʺ which pick‐up their high‐frequency sounds and let the scientist know if bats are just flying through an area or if they are actually catching insects.
How long do bats live?
The oldest bat caught in the wild was a banded myotis which was 39 years old at the time of recapture. To put this in perspective, a bat living longer than 30 years is equivalent to a human living longer than 100 years. Bats, for their size, are the world’s longest‐lived mammals. Yet unlike other mammals of their size, bats have very low reproductive rates, females of most species producing just one pup per year.
Where do bats live?
Not all bats spend their days roosting in caves. Some roost in trees, abandoned mines, buildings, bridges....the list goes on and on. Actually, the variety of bat roosts reflects the amazing diversity of bat species. Bats are highly opportunistic and have adapted to their environments in creative ways in order to take advantage of the many shelters available to them. Southern yellow bats (Lasiurus ega) roost in the hanging dead fronds of palm trees. Other bats, such as Honduran white bats (Ectophylla alba), chew the midribs of heliconia leaves in order to collapse them into waterproof tents far above the grasp of their predators. Evening bats (Nycticeius humeralis) raise their young under the bark of trees. Some bats even take shelter in the abandoned homes of other animals. For example, the big brown bat (Eptesicus fuscus) occasionally lives inside woodpecker holes in giant cacti. In southeast Asia, tiny club‐footed bats (Tylonycteris sp.) roost inside the hollow joints of bamboo stems once occupied by beetles. In Africa, small wooly bats (Kerivoula sp.) use spider webs as roosts. Each species has its own special requirements. Many bat populations are threatened due to loss of their specific roosting habitats. Scientists have studied the roosting requirements of a number of bat species in order to provide appropriate artificial homes for bats. These homes are called bat houses and have proven to be very successful for some species, if placed in appropriate locations.
How large are bats?
The largest bat living in the United States is the western mastiff bat (Eumops perotis), weighing approximately 2 ounces. It has a wing span of nearly 2 feet. However, other bats in the world can be much larger; one fruit‐eating flying fox (Pteropus vampyrus) has a wingspan of six feet! The smallest bat lives in Thailand and is called the bumblebee bat (Craseonycteris thonglongyai). This insectivorous bat has a wingspan of only 6 inches and weighs less than a penny.
What are flying foxes?
The common name “flying fox” refers to a group of bats living in the Old World tropics of Australia, Africa, Asia, and the South Pacific Islands. These bats received their common name because their faces resemble those of little foxes. They have large eyes because they do not use echolocation. Instead, they depend on vision and their keen sense of smell to find ripe fruit. Flying foxes help the ecosystems in which they live by pollinating many flowers and spreading seeds to new locations, especially aiding in rain forest regeneration.
Do bats make good pets?
It is important for people to remember that bats are wild animals and should be allowed to live in their natural environments. In fact, it is illegal in many countries to have a bat as a pet. Bats that can be caught are most likely sick and they should not be handled.
What is guano?
Guano is the collective term used for bat or bird droppings or feces. For many years, people all over the world have been using guano to fertilize their crops. Today, scientists also are able to extract enzymes from bacteria which live only in guano in order to make laundry detergents and other valuable products.
Will attracting bats to bat houses in my yard increase the likelihood that they will move into my attic or wall spaces?
No. If bats liked your attic or wall spaces, they probably would already be living there.
How many bats can potentially occupy my bat house?
A single-chamber house can shelter 50 to 100 bats, while a larger multi-chamber design can attract colonies of 200 or more bats.
How can I determine the likelihood of attracting bats?
Throughout most of the United States and much of Canada there are occupied bat houses being used by one of North America’s many crevice-dwelling bat species. Wherever bats live, they must find enough insects to eat, largely explaining their preference for roosting near aquatic habitats. The closer you live to cave or mine hibernating sites the better, and the existence of bat colonies in nearby buildings and bridges also increases your chances.
Why might bats not be attracted to my bat house?
The most frequent cause of failure is inappropriate exposure to solar heating. Alternatively, bats may not be able to live in your area due to heavy pesticide use, inadequate food supply or lack of available caves and mines within 50 to 100 miles (80 to 160 km). So far, we are unaware of large areas of North America (except for hot desert lowlands) that cannot attract bats.
If I have bats living in my attic, but would prefer that they occupy a bat house, what should I do?
Attics and other parts of buildings often provide ideal bat roosting sites. In most cases, bats will not voluntarily move from an attic. In such cases, alternative roosts ideally should be provided several months or one season before the desired move. The bats should be evicted from the attic at a time in the early spring or fall when flightless young are not present. Eviction is often easily accomplished. Watch to see where the bats emerge at dusk. Using 1/6" (4 mm) or smaller plastic mesh, bird netting or clear, heavy plastic, hang a large enough piece over the emergence point, extending a foot (30 cm) below and to each side of the exit. Secure the net in place so that it hangs free an inch (25 mm) or so away from the building. It will act as a one-way valve, permitting exit, but closing when bats land on it to return.
How effective are bats in controlling insects?
As primary predators of night-flying insects, bats play a key role in the balance of nature, consuming vast quantities of insects, many of which are costly agricultural and yard pests. Furthermore, many insects avoid areas where they hear bats.
Will having bat houses in my yard interfere with attracting birds?
No. They rarely compete for food or space.
Will bat droppings pose a threat to my family?
No more so than bird or cat droppings would. You should avoid inhalation of dust associated with animal feces of any kind.
What are the odds that a sick bat will endanger my family with rabies?
Only 14 people in more than 50 years have contracted rabies from North American bat species that commonly live in bat houses. Like all mammals, bats can contract rabies, though very few do (less than half of one percent). Unlike many other animals, even rabid bats rarely become aggressive. They quickly die from the disease, and outbreaks in their colonies are extremely rare. The odds of being harmed by a rabid bat are remote if you simply do not attempt to handle bats. Any bat that can be easily caught should be assumed to be sick and left alone. We do not recommend attracting bats to places where curious children are likely to attempt handling them. With or without bats in your yard, the most important action you can take to protect your family from rabies is to vaccinate your family dogs and cats.
© Bat Conservation International, Inc.
Used with Permission.
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