Florida's Bats

Bats are the only flying mammal. That alone makes them unique, but it may not elicit admiration from everyone, especially those who don't know what bats are really like.

There's a good reason to appreciate bats. In Florida, we can enjoy one thing in particular they do for us: eat insects. Seventy percent of all the bats in the world eat insects. Bats are the most important controller of night-flying insects, including many crop pests. One little brown bat can eat 600 too 1,200 mosquito-sized insects every hour! Most insect-eating bats eat their body weight in insects each night.

There are 18 different species of bats that have been documented in Florida. Of these, 13 are considered to be resident. Of the remaining 5, 4 have been found in such low numbers that they are considered accidental species: the little brown bat (Myotis lucifugus), the northern long-eared bat (Myotis septentrionalis), the silver-haired bat (Lasionycteris noctivagans) and the federally endangered Indiana bat (Myotis sodalis). The Jamaican fruit bat (Artibeus jamaicensis) is a fruit-eating bat that is listed as being found in the Lower Keys; however, no determination has been made on whether this bat is accidental or a resident.

Bats can often be divided into 2 groups by roosting habits. Bats that live individually in leaves, palm fronds and Spanish moss are considered to be solitary or foliage-roosting bats. Bats that roost in groups or clusters are considered to be colony-roosting bats. It is important to understand the roosting habit when trying to locate and identify bats.

Solitary or Foliage-Roosting Bats

Solitary or foliage-roosting bats share general characteristics that aid them in solitary life. They tend to have more than one young at a time. They have thicker and often more fur than colony-roosting bats. They are also the most colorful and beautiful bats. With variations from the typical brownish color that most people associate with bats, these bats have fur color from bright red to frosted and tri-colored.

Solitary roosting bats mainly use trees as roosts but seldom use tree cavities. Most often, they hang under a large leaf or tree branch and blend in with their surroundings.

One of the most common solitary roosting bats in northern Florida is the eastern red bat (Lasiurus borealis), found in the northern two-thirds of Florida. As the name indicates, these bats are a bright orange-red. Unlike most bats, red bats are sexually dimorphic in color; males are more brightly colored than females, which are a dirtier, sandy red color. Red bats inhabit forests, forest edges and hedgerows. Red bats prefer to roost in the dense foliage of deciduous trees, with a preference for American elms, as their coloration allows them to blend in, often hanging by one foot and looking like a leaf. They are swift flyers and are often seen foraging around streetlights.

Another common solitary roosting bat is the Seminole bat. This bat is found throughout the state and looks much like the eastern red bat except that its coloration is a deeper auburn-mahogany color. Unlike the eastern red bat, the Seminole doesn't vary in color between the sexes. Seminole bats are found in lowland, semi-forested and forested areas. They are greatly associated with the distribution of tree-hanging Spanish moss, which they use as roosts, especially in longleaf pines and oaks that border a clearing. Seminole bats emerge early to forage, often concentrating above the tree crowns.

Although found throughout the state, the most common species of solitary bat found in southern Florida is the northern yellow bat. These bats are yellow to dirty blonde in color and are larger than the red and Seminole bats. You'll find northern yellow bats in semi-forested and forested areas, usually near a permanent water source. You may also see them in abundance in orange groves and pastures. Northern yellow bats roost in Spanish moss, especially longleaf pine and turkey oak trees. They also roost in dead fronds that lay against palm trees. Sometimes there may be many females with young roosting in the moss of a tree, although roosting separately. Yellow bats forage over open areas containing a few shrubs and a scattering of trees, favoring forest edges, pastures, lake edges and golf courses.

The most beautiful of Florida's bats is the hoary bat. Hoary bats can't be easily confused with any other bat in Florida. Their fur is a mixed brown-gray color with heavy white fringe, giving them a frosted appearance. Hoary bats are not considered residents because they are found in Florida only during the spring and autumn when they migrate to and from Mexico and South America, where they spend the winter months. Hoary bats inhabit both deciduous and coniferous forests, and roost in trees that border clearings and have dense leaf coverings. Hoary bats forage above treetops along streams, lake shores and in urban areas where there are a lot of trees.

Colony-Roosting Bats

Colony-roosting bats tend to be darker in color, often brown, with no fur on the wing or tail membranes. These bats prefer to live in crevices such as tree hollows, woodpecker holes, caves and the underside of bridges. Colony-roosting bats are the types of bats that people encounter most often because these bats are also adaptable to buildings.

Most people believe that all or most bats live in caves. In fact, only 3 Florida species use caves for roosts. The federally endangered gray bat (Myotis grisescens) is one of a few species that live in caves year-round. Most of Florida's gray bat population is found in Jackson County, on the Florida/Georgia border west of Tallahassee. The foraging habitat of gray bats is over riparian areas (river banks) and often over water. Cave exploration, opening caves to the public and flooding of caves due to dams have caused serious a decline in the gray bat population. Due to protection and cave-gating programs, like those at Florida Caverns State Park in Jackson County, some populations of gray bats are now stable and may be increasing.

Other primarily cave-roosting bats are the southeastern myotis and the eastern pipistrelle. The southeastern myotis is usually found in the northern half of the state and tends to live near streams, ponds and reservoirs. Most often, maternity colonies are located above water within caves. Southeasterns have also been found roosting in buildings, culverts, bridges, old mine shafts and hollow trees in areas where caves are not abundant; however, these roosts are rare for this species. They begin feeding later in the evening and usually fly within 2 feet of the surface of water to catch insects. Even though this species is listed as of special concern, Florida has the highest concentration of these bats -- and their maternity caves -- in the world.

The eastern pipistrelle, Florida's smallest bat, is a dainty yellowish- to light-brown-colored bat found throughout most of the state. Its individual hairs are tri-colored, giving the appearance of rings when the fur is blown on. Even though considered to be solitary in nature, they form small maternity colonies, usually no greater than 20 individuals. Summer colony roost sites include hollow trees, the underside of tree bark, manmade structures, the underside of shingles and Spanish moss. Colonies are often in the open and are exposed to more light than other bat species are exposed to. They often use caves as winter roosts. They are one of the first to come out at night and are slow flyers with a somewhat erratic flight pattern. And they are sometimes mistaken for moths due to their small size!

The big brown bat is found in a wide range of habitats of the northern two-thirds of Florida. They occupy farmlands, cities, parks and forests. Typical roosts are bridges, tree hollows, snags, attics, barns or other manmade structures, as these bats are very adaptable. They also use night roosts. After a big brown bat has filled its stomach, it roosts in garages, breezeways, porches or other structures while it digests its food. This species usually takes the same foraging routes night after night. Foraging starts anywhere from 20 minutes to one hour after sunset, though as with other bats, they don't forage in the rain or cold temperatures.

The Rafinesque's big-eared bat (Corynorhinus rafinesquii) is another that can't be mistaken for any other Florida bat. The most noticeable feature of this bat is its ears, which are more than an inch long. The Rafinesque's big-eared bat inhabits forested regions of pine flatwoods and hardwood hammocks, roosting in hollow trees, crevices behind bark, buildings and other manmade structures, and under dry leaves. You might find these bats roosting with eastern pipistrelles and southeastern myotis. They begin feeding later in the evening, well after dark. These bats are gleaners and can sometimes be seen hovering to pick off insects from leaves -- they are slower flyers with excellent maneuverability that allows them to fly close to vegetation.

A common species found throughout the state is the evening bat. These dark-brown bats are small, making people think they are young when they come across them. Evening bats are found in temperate deciduous woodlands or mixed woodlands and open areas. Roosting preferences are tree hollows, especially in cypress trees, but they have adapted also to using manmade structures.

There are 3 kinds of bats in Florida that have a tail that extends out from the tail membrane, unlike most bats, which have tail membranes that enclose the tail. These bats are in the family of free-tailed bats. Pallas' mastiff bats are found only in the Keys and live in tree hollows, crevices and palm fronds. They are mostly associated with manmade structures, as the known colonies of these bats in the Keys are found in roofs and wall spaces of buildings. Roost temperatures may reach up to 131degrees F. Pallas' mastiff bats forage near water and in both deciduous and evergreen forests.

The Wagner's mastiff bat is Florida's largest bat and is found in southern Florida. These bats have a loud, piercing call that is easily picked up by human ears. The roosting preferences for these bats are barrel-tile roofs, tree hollows, and holes and shafts of royal palm trees. They emerge to forage much later than most bats, leaving well after dark. They seldom forage lower than 30 feet. These bats can take flight from horizontal surfaces, a feat most of our bats can't do easily. These bats are of special concern and are protected within the state of Florida. The loss of older trees, which are more likely to have roosting cavities, is thought to contribute to the decline in numbers of this species. If you find a colony of Wagner's mastiff bats, please contact the Organization for Bat Conservation (OBC) Florida Bat Center. (Please see contact information below.)

One of the most abundant bats in Florida is the Brazilian free-tailed bat. Found throughout the state, the roosting preferences for these adaptable bats are barrel-tile roofs, buildings, tree hollows, holes and manmade structures. Brazilian free-tailed bats tolerate warm temperatures (above 100 degrees F) very well. They are active all night and can forage up to 150 miles away, though most forage within 50 miles. These bats are most often found roosting with evening bats.

Bat Conservation

Disturbance or destruction of roost sites due to development and vandalism is the greatest threat to our bats. Most bats living in Florida prefer to roost in mature or dead trees or in caves. However, many bats are forced to take up residence in our homes or other buildings due to loss of these types of habitat. You can help bats by putting up bat houses. This provides bats with a safe place to live. The bat in turn eats many insect pests in your area.

Bats are disappearing at alarming rates, not only because of habitat loss, but also because they are persecuted by humans out of fear and misconceptions. Education is the main focus of the OBC Florida Bat Center. Educators travel throughout the state to spread the word about these beneficial animals. The Florida Bat Center also rehabilitates bats and performs field research and surveys. To learn more about bats, bat houses or other bat-related products, visit the Web site linked above. If you are interested in the educational programs the Florida Bat Center provides, please call 941-627-9455.

Bat Myths

There are many myths and misconceptions regarding bats. Many tales and movies have led most people to fear them. Bats, however, are very beneficial creatures and just need some understanding from us.

• Bats aren't blind. They enjoy the same senses we do: tasting, smelling, hearing, feeling and, yes, seeing.
  
  
• Bats are clean animals.
  
  
• Some bats, like the bats found in Florida, have a highly developed navigation and prey-detection system called echolocation. Bats don't fly into your hair or build nests in your hair, and they don't attack people. They actually are quite timid and want nothing to do with us.
  
  
• Bats are not flying rodents. They are more closely related to primates (or people), than to rodents, having one baby (pup) a year.
  
  
• There are no vampire bats in the United States. They are found only in Mexico and Central and South America. Vampire bats don't suck blood; they lap it up much like a dog laps water.

The most common misconception is that all or most bats have rabies. A very small percentage of bats gets rabies. However, just like any other mammal, once a bat gets rabies, it dies. Always make sure not to handle or play with any wild animals, including bats. They are wild and meant to be left alone. If you find a bat that you believe to be injured or hurt, please do not touch it, but instead contact the OBC Florida Bat Center.

Written By

Denise R. Tomlinson is the biologist for the OBC Florida Bat Center. Orginally from Michigan, she now calls southwest Florida home. She loves the adundance and diversity of Florida's wildlife. Bats are her passion, and she has a special fondness for Old World fruit bats (like the one pictured with her) and bats belonging to the genus Lasiurus, especially red bats. (Photo copyright Jerry Lee Gingerich, DVM)