Noctilio leporinus
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The greater bulldog bat or fisherman bat (''Noctilio leporinus'') is a species of fishing bat native to
Latin America Latin America or * french: Amérique Latine, link=no * ht, Amerik Latin, link=no * pt, América Latina, link=no, name=a, sometimes referred to as LatAm is a large cultural region in the Americas where Romance languages — languages derived f ...
(Spanish: ''murciélago pescador''; Portuguese: ''morcego-pescador''). The
bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...
uses echolocation to detect water ripples made by the fish upon which it preys, then uses the pouch between its legs to scoop the fish up and its sharp claws to catch and cling to it. It is not to be confused with the lesser bulldog bat, which, though belonging to the same genus, merely catches water insects, such as water striders and water beetles. It emits echolocation sounds through the mouth like '' Myotis daubentoni'', but the sounds are quite different, containing a long constant frequency part around 55 kHz, which is an unusually high frequency for a bat this large.


General description

The greater bulldog bat is a large bat, often with a combined body and head length of . It generally weighs from . Males tend to be larger than females, with the former averaging and the latter averaging . They also differ in fur color. Males have bright orange fur on the back while females are dull gray. However, both sexes have pale undersides and may have a pale line that runs down the middle of the back. The males do not have a baculum. The bulldog bat has rounded nostrils that open forward and down. It has elongated, pointed ears with a tragus that gets ridged at the outer edge. The bulldog bat has smooth lips but its upper lip is divided by a
skin fold Skin folds or skinfolds are areas of skin that are naturally folded. Many skin folds are distinct, heritable anatomical features, and may be used for identification of animal species, while others are non-specific and may be produced either by ind ...
while its bottom lip has a wart above skin folds that extend to the chin. It is these features that give the bulldog bat its name, as it resembles a
bulldog The Bulldog is a British breed of dog of mastiff type. It may also be known as the English Bulldog or British Bulldog. It is of medium size, a muscular, hefty dog with a wrinkled face and a distinctive pushed-in nose. When in flight, the bat's wings move slowly. This species is a capable swimmer and will use its wings to paddle. The greater bulldog bat also has prominent cheek pouches which are useful for holding its food. Its hind legs and feet are particularly large, capable of 180° rotation when hunting. The leg bones are significantly compressed in order to be streamlined towards the dragging direction.


Distribution and variation

The greater bulldog bats range stretches from Mexico to Northern Argentina and also includes most Caribbean islands. While vast, its range is also patchy as the bat is limited to mostly well-watered lowland and coastal areas as well as river basins. There is geographical variation in the species and are classified as subspecies. Bats around the Caribbean Basin are large and usually have the pale mid-dorsal stripe, despite varying in pelage. These bats are known as ''N. l. mastivus''. In Guianas and the Amazon Basin, the bats are small and dark and often lack the pale mid-dorsal stripe. These bats are known as ''N. l. leporinus''. In eastern Bolivia, southern Brazil and northern Argentina bats tend to be large and pale, more so than the other subspecies. They are known as ''N. l. rufenscenes.


Ecology and behavior

The greater bulldog bat lives primarily in tropical lowlands. The bats are commonly found over ponds and streams as well as estuaries and coastal lagoons. They live in colonies that number in the hundreds. In Trinidad, bulldog bats rest in hollow trees like silk-cotton,
red mangrove Red mangrove may refer to at least three plant species: * ''Rhizophora mangle'' * ''Rhizophora mucronata ''Rhizophora mucronata'' (loop-root mangrove, red mangrove or Asiatic mangrove) is a species of mangrove found on coasts and river banks in ...
and balatá. The bats live in hollow tree roosts in other areas as well. They also roost in deep sea caves. Like most bats, bulldog bats are nocturnal. Female bulldog bats stay together in groups while roosting and tend to be accompanied by a resident male. Females associate with the same individuals in the same location for several years unaffected by changes in resident males and movements of the group to different roosts. A male may stay with a female group for two or more reproductive seasons. Bachelor males are segregated from the females and may roost alone or together in small groups. Female bats forage either alone or with their roost mates, with stable female groups continue to forage in the same areas in the long term. Males forage alone and use areas that are larger and separate from those used by the females.


Food and hunting

The greater bulldog bat is one of the few bat species that has adapted to eating fish. Nevertheless, the bats eat both fish and insects. During the wet season, the bats feed primarily on insects like
moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...
s and
beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s. During the dry season, bat will primarily feed on fish as well as crabs,
scorpion Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always en ...
s and shrimp to a lesser extent. The bulldog bat mostly forages for fish during high tide and locates them with echolocation. A bulldog bat will fly high in the air and in a circular direction when searching for prey. If it spots a jumping fish, the bat will drop down closer to the water surface, particularly the spot where it made the jump and decreases the pulse duration and intervals of its echolocation signals. The bulldog bat may also search by dragging its feet across the water surface, a behavior known as raking. The bat may rake through areas where fish jumping is most frequent or in areas where it had previously made a successful catch.


Echolocation

Greater bulldog bats emit echolocation signals that are either at constant frequency (CF), frequency-modulated (FM) or a combination of the two (CF-FM). The longest signals are the pure CF signal which typically last 13.3 ms but can go as long as 17 ms. CF-FM signals have CF followed by an FM. In a CF-FM signal, the CF are typically 8.9 ms with a frequency of 52.8–56.2 kHz while the FM ranges up to 3.9 ms with 25.9 kHz bandwidth. Bulldog bats have two kinds of signal when flying. In one, the CF pulses begin at 60 kHz of frequency and may fall no further than 50 kHz. The second type has the CF starting at a frequency of 60 kHz and then falls for more than a single octave.


Reproduction

For females, pregnancy occurs from September until January, and lactation starts in November and continues until April. Only one young is born each gestation. Male bats mostly breed autumn and winter. Young bats stay in the roosts for one month and are then capable of flight. Both the male and female care for the young.


Status

While the bulldog bat is not in danger overall, the bat is nevertheless threatened by water pollution, persecution, changing water levels, cave disturbances, and
deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated ...
.


References


External links

{{Taxonbar, from=Q1073474 Bats of South America Bats of Brazil Mammals of Colombia Mammals of Guyana Noctilionidae Bats of Central America Mammals described in 1758 Taxa named by Carl Linnaeus Mammals of the Bahamas Mammals of the Dominican Republic Mammals of Haiti