Noctilio albiventrislesser bulldog bat

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Geographic Range

The lesser bulldog bat is a neotropical mammal. Its range extends from southern Mexico, to eastern Brazil then south into northern Argentina and Peru (Wilson and Reeder 1993).

Habitat

This species is found in a variety of vegetation types throughout its range, but it is always located near streams, bodies of water or other moist places. Bulldog bats typically roost in hollow trees, foliage and man-made structures. Members of this species have been found in association with the mastiff bat Molossus molossus; the roost can easily be identified by the musky odor of the lesser bulldog bat (Nowack 1994).

Physical Description

Forearm length: 54-70 mm.

The upper parts of N. albiventris are grayish brown to yellowish in color or bright red. Typically color is sexually dimorphic, with males being bright red and females dull brown and drab. Individuals have a paler middorsal line and paler underparts. The nose of these bats is very pointy, but has no nose leaf or other projections. The tail extends about half of the length of the well-developed uropatagium. The relatively short hind limbs are almost completely free from the wing membrane. The wings of N. albiventris are long and narrow in comparison to other families within Microchiroptera. Noctilio albiventris can be distinguished from its close relative N. leporinus by its smaller size, smaller hind limbs and smaller claws on the hind feet (Nowak 1994).

  • Range mass
    18 to 44 g
    0.63 to 1.55 oz
  • Range length
    57 to 85 mm
    2.24 to 3.35 in

Reproduction

Little else is known about the reproductive strategy of N. albiventris, however the mating system of its close relative N. leporinus is documented. Noctilio leporinus live in single-male/multiple-female groups in year-round harems with stable female composition (Walker 1964).

The reproductive behavior of N. albiventris is highly synchronous. These bats have a well defined breeding season with mating occurring in late November or December and birth occurring in late April or early May (Hooper and Brown 1968). Lactation continues for 3 months, and then juveniles are weaned. Only 1 young is born per year (Walker 1964). Young probably reach sexual maturity after their first year of life. At birth lesser bulldog bats have eyes that are barely open, ears that are incompletely developed and a distinct lack of hair. The baby bats are relatively slow to acquire fur and to attain the proportions of an adult. Most are able to fly 35 to 44 days after birth. Although echolocation is an important tool utilized in flight by adult bats, baby bats cannot fly and therefore do not emit echolocation signals. Newborn bats do not even show a behavioral or physiological response to sound until they are a week old. Vocal, auditory and motor systems appear to develop at a similar rate, resulting in a juvenile bat that is able to forage 3 to 6 weeks after birth (Brown et al. 1983).

  • Breeding season
    Mating occurs from November to December and births occur from April to May.
  • Average number of offspring
    1
  • Range gestation period
    4 to 5 weeks
  • Average weaning age
    3 months
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

This species is relatively altricial. Young are born helpless and are nursed and cared for by their mother until they reach independence.

Lifespan/Longevity

Noctilio albiventris individuals can live 10-12 years in the wild (Brown et al. 1983).

Behavior

Noctilio albiventris have been noted foraging with 8-15 conspecifics. Studies of the activity pattern of this species show a peak in activity immediately after sundown (Hooper and Brown 1968). This social and nocturnal mammal has developed an intricate communication system that is discussed below.

Communication and Perception

Food Habits

Noctilio albiventris individuals use echolocation to locate insects near the surface of the water. Although the other member of this genus, N. leporinus, is piscivorous, N. albiventris is primarily insectivorous. The feeding behavior of N. albiventris is flexible. Aerial capture is used as the primary foraging strategy, but if an insect falls to the surface of the water, N. albiventris is able to quickly change its foraging strategy to capture the insect by scooping it up from the surface of the water (pointed dip) or by raking the surface of the water with its hind claws (directed random rake) (Lewis-Oritt et al. 2001). This behavioral plasticity is thought to be a precursor to the evolution of piscivorous feeding behavior in N. leporinus (Kalko et al. 1998). In laboratory studies, N. albiventris has been trained to take floating fish from the surface of the water (Suthers and Fattu 1973) and researchers have identified fish scales in N. albiventris guano. There have been limited observations of these bats taking fish in the wild (Galileu Coelho, pers. comm.). Based on studies of the stomach contents of N. albiventris, most of the diet is derived from insects (Nowak 1994).

  • Animal Foods
  • fish
  • insects

Predation

Predators of bats are typically either terrestrial predators that take young from roosts, such as snakes, raccoons, ringtail cats, or small cats, or avian predators that take adults on the wing, such as falcons, hawks, or owls.

Ecosystem Roles

Lesser bulldog bats are important predators of insects in the ecosystems in which they live.

Economic Importance for Humans: Positive

Direct economic impact of this species has not been determined. However, these bats serve an important pest management function throughout their range and can produce commercially valuable guano.

  • Positive Impacts
  • produces fertilizer
  • controls pest population

Conservation Status

This species is currently not listed.

Contributors

Barbara Lundrigan (author), Michigan State University, Amy Kamarainen (author), Michigan State University.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

altricial

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.

bilateral symmetry

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

endothermic

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.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Brown, P., T. Brown, A. Grinnell. 1983. Echolocation, development, and vocal communication in the lesser bulldog bat, *Noctilio albiventris*. Behavioral Ecology and Sociobiology, 13(4): 287-298.

Crichton, E., P. Krutzsch. 2000. Reproductive Biology of Bats. Academic Press.

Hooper, E., J. Brown. 1968. Foraging and Feeding in two sympatric species of neotropical bats, genus *Noctilio*. Journal of Mammalogy, 49: 310-312.

Kalko, E., H. Schnitzler, I. Kaipf, A. Grinnell. 1998. Echolocation and foraging behavior of the lesser bulldog bat, *Noctilio albiventris*: preadaptations for piscivory?. Behavioral Ecology and Sociobiology, 42(5): 305-319.

Lewis-Oritt, N., R. Van Den Bussche, R. Baker. 2001. Molecular evidence for piscivory in *Noctilio* (Chiroptera: Noctilionidae). Journal of Mammalogy, 82(3): 749-759.

Nowack, R. 1994. Bats of the World. The Johns Hopkins University Press.

Suthers, R., J. Fattu. 1973. Fishing behavior and accoustic orientation by the bat (*Noctilio labialis*). Animal Behaviour, 21: 61-66.

Wilson, D., D. Reeder. 1993. Mammal Species of the World: Second Edition. Washington, D.C.: Smithsonian Institution Press.