Fringe-lipped bats (Trachops cirrhosus) are widespread in the tropical, lowland forests of Central and South America. They are distributed from Oaxaca (southern Mexico) through the Isthmus and in tropical regions of South America, reaching southeastern Brazil and Trinidad. They are a native species in all of these ranges and a common member of most Neotropical bat communities. (Cramer, et al., 2001; Miller, et al., 2015)
Fringe-lipped bats are mainly found in terrestrial habitats, such as tropical evergreen forests, as well as dry, deciduous forests near moist habitats. Because of these moist conditions, fringe-lipped bats predominantly roost in hollow trees, caves, and sometimes in abandoned road culverts and buildings. In these regions, they fly low through the forest understory to forage over streams and other wet areas. Larger colonies are usually found in deeper caves compared to smaller colonies of about six individuals or less. Fringe-lipped bats are uncommon in agricultural areas and at higher elevations.
Fringe-lipped bats are typicaly found at elevations of 500 m to 1,400 m. In Venezuela, they have been reported below 500 m and have been found at sea levels of 330 m in Belize. In Chiapas, Mexico, they were discovered at sites with an average elevation of 300 m. (Cramer, et al., 2001; Jones, et al., 2017; Miller, et al., 2015)
Fringe-lipped bats are medium-sized bats, with an average head and body length of 76 to 88 mm, a short tail length of 12 to 21 mm, and forearm length of 57 to 64 mm. The maximum recorded length of these bats is about 100 mm, and they weigh 32 to 45 g, with an average of 32.3 g. The dorsal region of fringe-lipped bats is a dark reddish-brown color to a dark brown, and the ventral region is a dull brown with gray. Their fur is long and woolly, extending along their forearms for half the length of the body.
Fringe-lipped bats also have a leaf nose, with serrated edges. In addition, their ears are large and longer than their heads; the tragi of their ears are pointed. The feet of fringe-lipped bats are big with short claws, and they have broad wings. They have a low wing-aspect ratio and high wing loading (their body mass is high compared to their total wing area). The name "fringe-lipped bat" comes from the cylindrical or conical, wart-like bumps on their lips and chin. Another distinguishable feature is the position of an unusually small, second lower molar in their mouths. There are two pairs of lower incisors with three pairs of lower premolars, which have tubercular depressions with W-shaped cusps.
In regards to sex differences, no true sexual dimorphism has been observed. Using evidence from populations of fringed-lipped bats from northeast Brazil have indicated no sexual dimorphism between sexes. (Cramer, et al., 2001)
Olfactory cues are important for fringe-lipped bats - they use scent to communicate their reproductive status and facilitate mate choice. An odorous substance is found on the forearms of reproductive male fringe-lipped bats, termed “forearm crust.” The forearm crust is currently found only in adult males. All males with forearm crust also have enlarged testes, indicating a strong association with sexual maturity and readiness for mating. It is suggested that males create a forearm crust to court females, or to compete with other males for access to females. Due to the importance of the lactation period for females and weaning period for pups, pregnancy is at the beginning of the wet season, as wet season is the best time of year for females to lactate and wean young. This is because prey species, especially frogs, are abundant. (Cramer, et al., 2001; Flores, et al., 2019)
Fringe-lipped bats breed during the dry season in the tropics, usually from January to June. Breeding males have also been reported in Trinidad during December and in Ecuador during February. There is a single peak in pregnancy during this time. The breeding season is directly related to the seasonality of fruit production. The gestation length of fringed-lipped bats is currently unknown, but by comparing observations to reproductive patterns of other leaf-nosed bats, it has been inferred that gestation is approximately 4 to 6 months.
The glands that have been described in bats are sexually dimorphic, with adult males having enlarged glands. Their chest glands are only a sexually dimorphic feature after reproductive maturity. Active chest glands in both female and male fringe-lipped bats secrete a white, oily, odorless exudate. After maturation, all reproductive females have rudimentary glands that are barely visible and do not produce any secretions. The secretion of the chest glands in these bats is not odorous. No specific evidence has been reported on when exactly weaning occurs, when independence occurs, and at what age they reach sexual maturity. It can be inferred that age of sexual maturity is similar in males and females. (Cramer, et al., 2001; Flores, et al., 2019)
The reproductive pattern of fringe-lipped bats is bimodal polyestry, in which females can have two pregnancies within a breeding season and give birth to a single offspring per litter. Females and their young form maternity colonies, which is a sub-area of larger colonies. Some evidence also indicates that pups associates with parents for a considerable period, but it is not specified exactly how long.
Pups drink milk from their mother because their wings are not fully developed when they are born, so they cannot forage on their own. While their mothers are caring for them, pups cling to a nipple to feed and receive warmth. When mothers forage for food on late evenings, babies will hang from the walls of the nursery roost. (Cramer, et al., 2001)
Not much is known about the exact lifespan of fringe-lipped bats. However, the typical wild lifespan of bats in the family of Phyllostomidae (new world leaf-nosed bats) is 20-30 years.
The longevity of fringe-lipped bats relies on returning to the same places to roost every year. Colonies are usually small, with fewer than six individuals of both sexes. (Cramer, et al., 2001; Miller, et al., 2015)
Fringe-lipped bats are a social species. Both male and female bats roost together in groups of up to 50 individuals. However, colonies are usually small, with fewer than six individuals of both sexes. However, there is evidence suggesting that fringe-lipped bats share their roosts with other bat species such as common vampire bats (Desmodus rotundus), hairy-legged vampire bats (Diphylla ecaudata), and pygmy round-eared bats Lophostoma brasiliense. They roost in hollow trees and fly a short distance (1 to 2 km) to their foraging grounds, where they catch prey over a relatively small area.
Fringe-lipped bats emerge from their roosts approximately 30 minutes after sunset, the ideal time to hunt frogs. Fringe-lipped bats hunt in continuous flight or sally out from perches, and hunt by following sounds of insects and frogs, with the help of echolocation.
It has also been found that individuals have unique associations with one another, which result in social learning. Inexperienced bats learn socially by observing experienced bats distinguish the calls of poisonous toads. (Cramer, et al., 2001; Surlykke, et al., 2013)
The home range of fringe-lipped bats extends from Mexico to Brazil, ranging over relatively large areas (456 ha) and long distances (>1.5 km) between roosts and feeding areas. (Jones, et al., 2017; Leal, et al., 2018)
Fringe-lipped bats communicate with each other via echolocation, one of the key adaptations for bats in general. They emit high frequency signals and use the returning echoes to orientate themselves in darkness, find roosts, and detect and localize prey.
Bats send out sound waves from their mouths or noses to communicate; when these waves come in contact with an object, they create echoes that are caught by their ears. Like other bats in the family Phyllostomidae, fringe-lipped bats have a leaf nose, which directs and focuses echolocation calls emitted from their nostrils. The nostrils of fringe-lipped bats play an important role in shaping and steering the sonar waves they emit. Fringe-lipped bats have also been observed to echolocate both with a closed and open mouth, which influences the sound emission by changing the emission site. They usually emit short, multiharmonic calls of low intensity.
Fringe-lipped bats also use echolocation while hunting. They listen to prey-emitted, acoustic cues to detect and localize prey, such as frogs and insects. Although these bats primarily use passive listening, they produce echolocation calls throughout their hunt. It has been tested in flight cage experiments that fringe-lipped bats can use echolocation, spatial memory, and chemical cues to detect silent prey upon approach. (Dixon, et al., 2019; Patriquin, et al., 2018; Surlykke, et al., 2013)
Fringe-lipped bats are generalist predators with a diverse diet, therefore making them an omnivore. Fringe-lipped bats are active predators of insects and small vertebrates, such as frogs and lizards. They also feed on fruits and seeds, birds, and other small mammals (including some bats). The remains of skin and hair of a furipterid bat (thumbless bat, or Furipterus horrens) were found in the stomach contents of one adult male collected at Rio Formoso, in northeastern Brazil.
Fringe-lipped bats primarily hunt stationary prey, using both continuous flight and perch hunting when foraging. They specialize on frogs - specifically túngara frogs (Engystomops pustulosus) - using echolocation strategies and sounds produced by prey when hunting.
Fringe-lipped bats are highly selective with respect to the type of frogs they consume; research suggests that they are able to discriminate between poisonous and palatable species, not only by mating calls, but also on the basis of touch and taste.
Radio-telemetry studies found that fringe-lipped bats make long flights early in the evening, hunting on wing over streams and ponds for frogs. Later in the night, when frog calling activity decreases, fringe-lipped bats switch to perch hunting for insect prey, such as forest katydids (family Tettigoniidae). (Bonato and Facure, 2001; Cramer, et al., 2001; Gomes, et al., 2016; Jones, et al., 2017; Rand, et al., 1982; Surlykke, et al., 2013)
There are currently no anti-predator adaptations found in fringe-lipped bats. There is also a lack of information on the specific predators that hunt fringe-lipped bats. However, in general, bats are eaten by a number of predators such as owls, hawks, snakes, and predatory mammals that climb into bat roosts during the day and attack bats when they are asleep. Thus, it can be inferred that fringe-lipped bats are hunted by larger, predatory birds and snakes in their habitats. (Cramer, et al., 2001)
Many research studies have been conducted on fringe-lipped bats, comparing this species with other bat species. Their behavior of eavesdropping on frog calls has made fringe-lipped bats a model for examining how predation can be a selective force on sexual advertisement signals of prey.
Fringe-lipped bats are important in ecosystems because of their role as a secondary consumer. Since they predominantly hunt for frogs in the evening, they help control populations in the frogs they hunt. This goes for insect prey as well, such as forest katydids.
Fringe-lipped bats are a source of food for other, larger predators, allowing for a more stable and healthier ecosystem. They currently have a high population count with a lack of threats, so it can be inferred that these bats are a good source of food for predators.
Fringe-lipped bats also roost with a variety of other species of bats. This suggests a mutualistic relationship between the species, such as providing food and protection for each other. Information still remains undiscovered about the benefits of fringe-lipped bats roosting together with other bats. (Cramer, et al., 2001; Miller, et al., 2015; Surlykke, et al., 2013)
Fringe-lipped bats have been observed for research in bat behaviors, predation, and mating. One study with fringe-lipped bats resulted in the conclusion that they are strong social learners of acoustic cues with the ability to identify prey calls. This suggests that heterospecific learning may occur in nature.
Another research project with fringe-lipped bats studied how they make decisions. It was discovered that, when given a choice between the calls of two species of frogs, fringe-lipped bats chose the more prominent call that was associated with a higher capture rate. This result challenges other experiments that suggest irrationality in animal decision-making.
Generally speaking, bat guano is used as fertilizer, which is important for agriculture in many countries. Furthermore, bats help pollinate crops and also control pest populations - especially mosquitoes. (Hemingway, et al., 2017; Jones, et al., 2017; Patriquin, et al., 2018)
Currently, there are no known adverse effects of fringe-lipped bats on humans.
Fringe-lipped bats are currently considered of "Least Concern" on the IUCN Red List. They occur in a number of protected areas, and have stable and high population sizes, with no major threats known throughout their range. (Miller, et al., 2015)
Fringe-lipped bats seem to be unusual among bats in their cognitive capabilities; their eavesdropping behavior requires bats to identify a variety of prey using their species-specific sexual advertisement calls. Observations of fringe-lipped bats suggest that they are perch-hunters that predominantly rely on prey-emitted cues, especially on frog sexual advertisement calls, which earned them the nickname, ‘frog-eating bats’. (Jones, et al., 2017)
Karen Yang (author), Colorado State University, Brooke Berger (editor), Colorado State University, Galen Burrell (editor), Special Projects.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
active at dawn and dusk
The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
an animal that mainly eats fruit
An animal that eats mainly plants or parts of plants.
An animal that eats mainly insects or spiders.
a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats all kinds of things, including plants and animals
having more than one female as a mate at one time
breeding is confined to a particular season
remains in the same area
offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
places a food item in a special place to be eaten later. Also called "hoarding"
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sound above the range of human hearing for either navigation or communication or both
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
Bonato, V., K. Facure. 2001. Bat predation by the Fringe-lipped bat. Mammalia, 64: 241-258. Accessed February 10, 2020 at https://www.degruyter.com/view/j/mamm.2000.64.issue-2/mamm.2000.64.2.241/mamm.2000.64.2.241.xml.
Cramer, M., M. Willig, C. Jones. 2001. Trachops cirrhosus. Mammalian Species, 656: 1-6. Accessed February 09, 2020 at https://www.researchgate.net/publication/232691526_Trachops_cirrhosus.
Dixon, M., K. Hulgard, J. Ratcliffe, R. Page. 2019. Habituation and ecological salience: insights into the foraging ecology of the fringed-lipped bat, Trachops cirrhosus. Behavioral Ecology and Sociobiology, 73.
Flores, V., J. Mateo, R. Page. 2019. The role of male forearm crust odour in fringe-lipped bats (Trachops cirrhosus). Behaviour, 156: 1435-1458.
Gomes, D., R. Page, I. Geipel, R. Taylor, M. Ryan, W. Halfwerk. 2016. Bats perceptually weight prey cues across sensory systems when hunting in noise. Science, 353: 1277. Accessed February 10, 2020 at https://www.sciencedaily.com/releases/2016/09/160915154232.htm.
Hemingway, C., M. Ryan, R. Page. 2017. Rationality in decision-making in the fringe-lipped bat, Trachops cirrhosus. Behavioral Ecology and Sociobiology, 71: 1-10.
Jones, P., F. Haemsch, R. Page, E. Kalko, T. O'Mara. 2017. Foraging and roosting behaviour of the fringe-lipped bat, Trachops cirrhosus, on Barro Colorado Island, Panama. Acta Chiropterologica, 19: 337-346.
Leal, B., E. Silva, L. Chaves, J. Gomes, P. Barros, D. Figueiredo, R. Lyra-Neves, W. Rodrigues, B. Moura, G. Jorge, G. Filho. 2018. The menu of Trachops cirrhosus (Chiroptera: Phyllostomidae) in the Caatinga, including a review from your diet. Neotropical Biology and Conservation, 13: 337-346.
Miller, B., F. Reid, J. Arroyo-Cabrales, A. Cuarón, P. de Grammont. 2015. "Trachops cirrhosus. The IUCN Red List of Threatened Species" (On-line). Accessed February 09, 2020 at https://www.iucnredlist.org/species/22029/22042903.
Patriquin, K., R. Page, J. Ratcliffe. 2018. Bats without borders: Predators learn novel prey cues from other predatory species. Science Advances, 4: 1-6.
Rand, A., M. Ryan, M. Tuttle. 1982. Bat Predation and Sexual Advertisement in a Neotropical Anuran. American Naturalist, 119: 136-139. Accessed February 09, 2020 at http://web.biosci.utexas.edu/ryan/Publications/1980-82/1982AmNat119-136.pdf.
Surlykke, A., L. Jakobsen, E. Kalko, R. Page. 2013. Echolocation intensity and directionality of perching and flying fringe-lipped bats, Trachops cirrhosus (Phyllostomidae). Frontiers in Physiology, 4: 143.