Mexican Free-tailed Bat - AbsoluteAstronomy.com

The Mexican free-tailed bat (Tadarida brasiliensis), also known as the Brazilian free-tailed bat, is a medium-sized bat

Bat

Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

that is native to the Americas

Americas

The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

and is widely regarded as one of the most abundant mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. However, its proclivity towards roosting in large numbers in relatively few roosts makes it especially vulnerable to human disturbance and habitat destruction and declining numbers at some roosts such as in the western state of Utah

Utah

Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

have been documented. In the western coastal state of California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, the bat is considered a species of special concern
California species of special concern
"Species of special concern" is a protective legal designation assigned by the California Department of Fish & Game to wildlife species that are at risk...

as a result of declining populations. The species' winter migratory habits and destination points are still relatively unknown. The Mexican free-tailed bat is the official state bat

U.S. state bats

As of February, 2011, at least three US states had an official bat. The general assembly of North Carolina considered a bill in 2007 that would have made Rafinesque's Big-eared Bat its state bat. The bill passed 92-15, but died in the state senate....

of both Oklahoma

Oklahoma

Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...

and Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, and its image is the icon for the Bacardi

Bacardi

Bacardi is a family-controlled spirits company, best known as a producer of rums, including Bacardi Superior and Bacardi 151. The company sells in excess of 200 million bottles per year in nearly 100 countries...

rum brand.

Physical description

Mexican free-tailed bats are about 9 cm (3.5 in) in length, and they weigh about 12.3 g (0.433869733892877 oz). The tails makes up almost half the length. Their ears are wide and set apart to help them find prey with echolocation

Animal echolocation

Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...

. The fur color varies from dark brown to gray. This species also has distinctive short snouts and wrinkled upper lips. The tail of the bat extends beyond the uropatagium, hence why they are named “free-tailed” bats.The wings are long, narrow and pointed, making them well-equipped for rapid, direct flight.

Range and ecology

The Mexican free-tailed bat is one of the most widespread mammals in the Western Hemisphere. The northern limit of its range extends from southern Oregon though Nevada northern Utah, northern Nebraska, Arkansas, northern Alabama, Mississippi, Georgia and into southern North Carolina. It has been claimed that bats in North Carolina are residents that have recently invaded the coastal plain and are not post-breeding vagrants. Extra-limital northern records of this bat have been documented Illinois, Iowa and South Dakota. From these northern limits, the range of the bat extends through most of Mexico, and through most of Central America. The range of the Mexican free-tailed bat in South America is less understood. It lives in four of seven of South America’s faunal provinces, including the eastern Brazilian highlands and coast, the eastern slopes of the Andes and the Pacific coast of Peru and northern Chile. It does not occur in much of the Amazon rainforest. The bat ranges widely across the Caribbean, and is native to all of the Greater Antilles and to 11 of the Lesser Antilles. The largest known colony is found at Bracken Cave

Bracken Cave

Bracken Cave is the largest known habitat for Mexican Free-tailed Bats. It is located in southern Comal County, Texas, outside the city of San Antonio. Bracken Cave houses a colony of over 20 million bats, making it the largest known concentration of mammals, except for humans...

, north of San Antonio, Texas

San Antonio, Texas

San Antonio is the seventh-largest city in the United States of America and the second-largest city within the state of Texas, with a population of 1.33 million. Located in the American Southwest and the south–central part of Texas, the city serves as the seat of Bexar County. In 2011,...

, with nearly 20 million bats; research indicates that bats from this colony congregate in huge numbers at altitudes between 180 and 1,000 m (590 and 3,300 ft), and even as high as 3,000 m (9,800 ft).

Habitat

Mexican free-tailed bats roost primarily in caves. However they will also roost in buildings. Any type of building is suitable for roosting as long as the bats have access to openings, to dark recesses in ceilings or walls. The age, height, architecture, construction materials, occupancy by humans and compass orientation apparently do not affect suitability for roosting. Caves occupied by this species need to be large enough to provide adequate wall and ceiling space for millions of bats. Hollows of trees such as red mangrove, black mangrove, white mangrove and cypress where probably the natural roosts for free-tailed bats in the southeastern United States. However most bats in Florida seem to prefer building and other man-made structures over natural roosts. Caves in Florida tend to be occupied mostly by the southeastern myotis

Southeastern myotis

The Southeastern Myotis is a small bat that is found throughout the Gulf Coastal Plain and the Lower Mississippi Alluvial Plain of the southeastern United States.-Description:...

. Caves in Florida tend to have pools of water on the floor and the free-tailed bats requires less relative humidity than the southeastern myotis.

Migration

Mexican free-tailed bats in southeastern Nevada, southwestern Utah, western Arizonia and southeastern California will form a unit and migrate westward and southward into southern California and Baja California. Bats in southeastern Utah, southwestern Colorado, western New Mexico and eastern Arizona migrate along the western side of the Sierra Madre Oriental

Sierra Madre Oriental

The Sierra Madre Oriental is a mountain range in northeastern Mexico.-Setting:Spanning the Sierra Madre Oriental runs from Coahuila south through Nuevo León, southwest Tamaulipas, San Luis Potosí, Querétaro, and Hidalgo to northern Puebla, where it joins with the east-west running Eje Volcánico...

into Jalisco, Sinaloa and Sonora. Some bats that summer in Kansas, Oklahoma, eastern New Mexico and Texas will migrate southward to southern Texas and into eastern central and perhaps western Mexico.

In Austin, Texas

Austin, Texas

Austin is the capital city of the U.S. state of :Texas and the seat of Travis County. Located in Central Texas on the eastern edge of the American Southwest, it is the fourth-largest city in Texas and the 14th most populous city in the United States. It was the third-fastest-growing large city in...

, a colony of Mexican Free-tailed Bats summers (they winter in Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

) under the Congress Avenue Bridge ten blocks south of the state capitol

Texas State Capitol

The Texas State Capitol is located in Austin, Texas, and is the fourth building to be the house of Texas government in Austin. It houses the chambers of the Texas Legislature and the office of the governor of Texas. It was designed originally during 1881 by architect Elijah E. Myers, and was...

. It is the largest urban colony in North America with an estimated 1,500,000 bats. Each night they eat 10000 pound of insects. Each year they attract 100,000 tourists who come to watch them. In Houston, Texas, there is a colony living under the Waugh Street Bridge over Buffalo Bayou

Buffalo Bayou

Buffalo Bayou is a main waterway flowing through Houston, in Harris County, Texas, USA. It begins in Katy, Fort Bend County, Texas and flows approximately east to the Houston Ship Channel and then into Galveston Bay and the Gulf of Mexico...

. It is the home to 250,000 bats and also attracts viewers. The Mexican Free-tailed Bat is the official "flying mammal" of the state of Texas

Texas

.

Bats ranging eastward from eastern Texas do not migrate but local shifts in roost usage often occur seasonally. Also, a regional population that ranges from Oregon to California, has a year round residence.

Diet

Mexican free-tailed bats are primarily insectivores. They hunt their prey using echolocation. The bats eat moth

Moth

A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

s, beetle

Beetle

Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

s, dragonflies

Dragonfly

A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...

, flies

Diptera

Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...

, true bug

Hemiptera

Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...

s, wasp

Wasp

The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

s, beetle

Beetle

s, and ants. Bats usually prey on flying insects when they themselves are in flight. Large numbers of Mexican free-tailed bats fly tens of meters above the ground in Texas to feed on migrating insects.

Health and mortality

The longest living individual bat lived for more than eight years, based on dental records. Predators of the bat include large bird such as red-tailed hawk

Red-tailed Hawk

The Red-tailed Hawk is a bird of prey, one of three species colloquially known in the United States as the "chickenhawk," though it rarely preys on standard sized chickens. It breeds throughout most of North America, from western Alaska and northern Canada to as far south as Panama and the West...

, American kestrel

American Kestrel

The American Kestrel , sometimes colloquially known as the Sparrow Hawk, is a small falcon, and the only kestrel found in the Americas. It is the most common falcon in North America, and is found in a wide variety of habitats. At long, it is also the smallest falcon in North America...

s, great horned owl

Great Horned Owl

The Great Horned Owl, , also known as the Tiger Owl, is a large owl native to the Americas. It is an adaptable bird with a vast range and is the most widely distributed true owl in the Americas.-Description:...

s, barn owl

Barn Owl

The Barn Owl is the most widely distributed species of owl, and one of the most widespread of all birds. It is also referred to as Common Barn Owl, to distinguish it from other species in the barn-owl family Tytonidae. These form one of two main lineages of living owls, the other being the typical...

s, and Mississippi kite

Mississippi Kite

The Mississippi Kite is a small bird of prey in the family Accipitridae. It is 12 to 15 inches beak to tail and has a wingspan averaging 3 feet . Weight is from 214 to 388 grams . Adults are gray with darker gray on their tail feathers and outer wings and lighter gray on their heads...

s. Mammalian predators include Virginia opossum

Virginia Opossum

The Virginia opossum , commonly known as the North American opossum or tlacuache in Mexico, is the only marsupial found in North America north of Mexico. A solitary and nocturnal animal about the size of a domestic cat, and thus the largest opossum, it is a successful opportunist...

s, striped skunk

Striped Skunk

The striped skunk, Mephitis mephitis, is an omnivorous mammal of the skunk family Mephitidae. Found over most of the North American continent north of Mexico, it is one of the best-known mammals in Canada and the United States.-Description:...

s, and raccoon

Raccoon

Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...

s. Snakes such as eastern coachwhips and eastern coral snakes may also prey on them, but predation is low. Certain types of beetles are important agents of mortality for neonate and juvenile bats that have fallen to the ground. This species seems to have a low amount of rabies, at least in the United States. They do however contain certain pesticides.

Behavior

Mexican free-tailed bats begin foraging at sunset and continue feeding throughout the night. When feeding they will fly over 50 km to a foraging area. They have straight, quick flights. This species has the highest recorded flight altitude among bats, flying at around 3300m. Bats in a Colorado mine have been documented being most active, mostly feeding and roosting, in the late morning and afternoon during the months of June through September. Free-tailed bats are more active in warm weather. The bats call, squeak, and move around during waking hours.

Mexican free-tailed bats are also great pollinators and dangerous insect eaters. Their pollination of sugar cane as well as their consumption of insects that damage sugar cane are the reasons why Bacardi

Bacardi

rum features the Mexican free-tailed bat as its icon.

Echolocation

Mexican free-tailed bats use echolocation for navigation and detecting prey. They emit brief constant frequency calls while traveling. However, they transfer to modulated frequency calls between 75–40 kHz when they detect food or another object. The normal frequency range of their echolocation tends to be between 49–70 kHz, but can drop to around 25–40 kHz.

Mating and reproduction

During the breeding season, male bats vocalize and mark territories in order to attract potential mates. Females gather in large groups at maternity roosts in caves. Smaller groups can be found in bridges, buildings, and other man-made structures as well as trees. Male and female call to one other and when they single out a mate they move away from the group. Mating can come in an aggressive or passive form. During aggressive copulation, the female is separated from a roost cluster by the male who restricts her movements during mating and produces characteristic calls. During passive copulation, a male will move very slowly onto a female that is roosting in a dense cluster. With passive copulations, there no resistance from the female and the males does not vocalize. Mating is likely promiscuous as both males and females mate with multiple partners. Female free-tailed bats become sexually mature at about nine months while males take even longer, at two years. Females have one annual estrous cycle that lasts around five weeks during ovulation. The sexual activity of males coincides with female receptivity in the spring. The gestation period of the bat last 11–12 weeks with a single young being born. Mothers leave their young with a larger cluster of other young, known as creches, rather than roosting with them. The female identifies her young through a series of calls and odors produced by the pup. The scent of the mother in imprinted on the young from an early age. However, young try to latch on to any female that passes in the cluster to try to get fed. Young are nursed daily and at 4–7 weeks old they reach adult size, are weaned, and are independent.

Protection

Though abundant and widespread, there are some local populations which have prompted protection and conservation efforts. For instance, during the spring and summer, one of the largest Mexican Free-tailed Bat populations inhabits Cueva de la Boca, a cave near Monterrey

Monterrey

Monterrey , is the capital city of the northeastern state of Nuevo León in the country of Mexico. The city is anchor to the third-largest metropolitan area in Mexico and is ranked as the ninth-largest city in the nation. Monterrey serves as a commercial center in the north of the country and is the...

, Mexico. In 2006, the Mexican environmental conservation NGO, Pronatura Noreste

Pronatura Noreste

Pronatura Noreste is a Mexican non-government, non-profit organization, recognized by the National Council of Science and Technology as a scientific and educational organization. Pronatura Noreste is one of six regional offices of the Pronatura family, and has its headquarters in Monterrey, Nuevo...

purchased the property. Because of a reduction of more than 95% of the original 20 million bat individuals population, as a result of vandalism, pollution, and uncontrolled tourism, the organization decided to buy the property in order to place it under conservation. Other species of high ecological value that inhabit the cavern are also being protected.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.