Generally, bats with long narrow wings are rapid, enduring fliers. The flight of greater bulldog bats has been described as rather stiff-winged and not particularly rapid. However, they are powerful. If knocked into the water, this bat can swim using its wings as oars, and it is capable of taking flight from water.
Regarding food habits, one study on the Island of Culebra, Puerto Rico, showed that during the wet season, the bat's diet was predominantly small insects, but during the dry season, pelagic and freshwater fish represented a greater portion of the diet. This indicates the bat has a flexible foraging strategy, allowing it to adjust to local conditions.
The roosts of greater bulldog bats are characterized by a strong musky odor. This odor comes from oily secretions found beneath the wings, in the subaxillary region. Female bats roost in groups that remain together associating with the same individuals and in the same location for years. Females scent mark their heads with the sub-axil secretions of other females. They do this by rubbing their heads under other bats' wings. These secretions have been found to differ between sexes. It has been suggested this scent may communicate information about sexual identity and reproductive condition. It may also allow bats to be recognized by their odor within the roost and while flying.
Males of this species have an unusual pocket-like fold of skin associated with the scrotum. Glands in this pocket also contribute to the obvious musky odor in males.
Another peculiar characteristic is that N. leporinus' sperm is unique among mammalian spermatozoa. The sperm head is extraordinarily large and flat. There is a large acrosome which lies anterior to the nucleus. This acrosome is shaped into a dozen accordion-like folds that run parallel to the long axis of the sperm. Researchers believe these acrosome ridges may strengthen the sperm head during transport.
Perception Channels: tactile ; chemical
These bats have no special conservation status. However, one report on the island of Curacao, Netherlands Antilles, showed that uncontrolled cave disturbance and removal of resources through development has brought about an apparent decrease in bat numbers.
CITES: no special status
IUCN Red List of Threatened Species: least concern
Groups of Noctilio leporinus may take significant numbers of small fish from hatcheries and aquaculture projects. Methods for blocking echolocation over hatchery ponds can be effective in preventing these losses.
None known.
Noctilio leporinus catches and consumes fish. It is one of about six bat species that regularly eat fish. It will also eat aquatic crustaceans, stinkbugs, crickets, scarab beetles, moths, winged ants, and other insects, but primarily, it is a piscivore (fish-eater).
Animal Foods: fish; insects; terrestrial non-insect arthropods; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
Noctilo leporinus is found in tropical and subtropical parts of the New World from Southern Vera Cruz (Mexico) to Northern Argentina and Southeastern Brazil. This species is also found on the Greater and Lesser Antilles, and the Bahamas.
Biogeographic Regions: neotropical (Native )
They roost near streams, coastal marine habitats, major river basins, or other moist places.
Average lifespan
Status: captivity: 11.5 years.
The sexes are slightly dimorphic in size, the males averaging larger than the females. A male weighing 78 g, and a female weighing 60 g were reported by Klingener, Genoways, and Baker (1978). Head and body length is 98 to 132 mm, and forearm length measures 70 to 92 mm.
The sexes are also dimorphic in color, with males having reddish to orange pelage dorsally, and females generally having greyish or dull brown fur. Both males and females tend to have paler underparts, and the pelage is extremely short.
Noctilionids have a pointed muzzle and lack a nose leaf. The nose is somewhat tubular and projects slightly beyond the lips. Upper lips are smooth but divided by a "hare lip", a vertical fold of skin under the nostrils. The lips are also large and swollen in appearance, suggesting the common name, greater bulldog bat.
This bat presents a formidable dentition. Its cheeks are elastic and can be greatly expanded. Internal cheek pouches are present. The ears are large, slender, pointed, and separate. There is also a tragus which has a serrated margin.
Noctilio leporinus has wings which are long and quite narrow, being more than two and a half times the length of the head and body. Nearly 65% of the wingspan is composed of the third digit.
The tail is more than half as long as the thigh bone. It extends to about the middle of a well-developed uropatagium, or tail membrane. The tail tip is free, protruding for about 10 to 15 mm from the dorsal surface of this membrane. The uropatagium is supported by the legs, tail, and calcar, or heel extension. The calcar is a cartilaginous structure that articulates with the heel bone (calcaneum) and is unique to bats. In this fishing species, the calcar is large and serves to hold the uropatagium out of the water as the bat flies close to the surface.
Noctilio leporinus has unusually long hind limbs and very large hind feet with strong gaff-like claws. Fishing bats tend to have hind feet 1.8 to 3.9 times larger than related non-fishing bats.
Range mass: 60 to 78 g.
Range length: 98 to 132 mm.
Sexual Dimorphism: male larger; sexes colored or patterned differently; male more colorful
Other Physical Features: endothermic ; bilateral symmetry
Average basal metabolic rate: 0.4 W.
Bachelor males roost apart from females. Males residing with female groups stay for two or more reproductive seasons. Female N. leporinus bear a single young each pregnancy. This appears to form the basis of a polygynous social organization.
This species tends to have pregnancies occuring from September until January, and lactation is first seen in November and continues until April. This is a general pattern, however, and it can vary with geographical location. Reproduction corresponds to seasons of greatest food availability.
Young bats don't leave the roost for their first attempts at sustained flight until nearly adult size. At that time they are slightly less than one month of age and the parents have remained at the roost throughout. This suggests a high degree of bi-parental care which may be a characteristic of this species.
Breeding interval: These bats apparently breed once per year.
Breeding season: Pregnancies occur from September until January, although the time of mating is apparently unreported in the literature.
Range number of offspring: 1 to 1.
Average gestation period: 2 months.
Average time to independence: 1 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Average number of offspring: 1.
The greater bulldog bat or fisherman bat (Noctilio leporinus) is a species of fishing bat native to Latin America (Spanish: murciélago pescador; Portuguese: morcego-pescador). The bat 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.
The greater bulldog bat is a large bat, often with a combined body and head length of 10.9 to 12.7 cm (4.3 to 5.0 in). It generally weighs from 50–90 grams (1.8–3.2 oz).[3] Males tend to be larger than females, with the former averaging 67 grams (2.4 oz) and the latter averaging 56 grams (2.0 oz).[4] They also differ in fur color. Males have bright orange fur on the back while females are dull gray.[5] However, both sexes have pale undersides and may have a pale line that runs down the middle of the back.[5] The males do not have a baculum.[6] 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 while its bottom lip has a wart above skin folds that extend to the chin.[5] It is these features that give the bulldog bat its name, as it resembles a bulldog.
The bulldog bat has a wingspan of 1 meter (3 feet). The wing of the bat is longer than the head and body combined and 65% of its wingspan is made of the third digit.[7] When in flight, the bat's wings move slowly.[7] This species is a capable swimmer and will use its wings to paddle.[5] The greater bulldog bat also has prominent cheek pouches which are useful for holding its food.[7] Its hind legs and feet are particularly large,[5] capable of 180° rotation when hunting. The leg bones are significantly compressed in order to be streamlined towards the dragging direction.[8]
The greater bulldog bat's range stretches from Mexico to Northern Argentina and also includes most Caribbean islands.[7] 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.[9] 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.[9] 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.[9] They are known as N. l. rufenscenes.
The greater bulldog bat lives primarily in tropical lowlands.[10] The bats are commonly found over ponds and streams as well as estuaries and coastal lagoons.[11] They live in colonies that number in the hundreds.[7] In Trinidad, bulldog bats rest in hollow trees like silk-cotton, red mangrove and balatá.[12] The bats live in hollow tree roosts in other areas as well.[7] They also roost in deep sea caves.[12] 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.[13]
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 moths and beetles.[3] During the dry season, bat will primarily feed on fish as well as crabs, scorpions and shrimp to a lesser extent.[3] 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.[14] The bulldog bat may also search by dragging its feet across the water surface, a behavior known as raking.[14] The bat may rake through areas where fish jumping is most frequent or in areas where it had previously made a successful catch.[14]
Greater bulldog bats emit echolocation signals that are either at constant frequency (CF), frequency-modulated (FM) or a combination of the two (CF-FM).[14] The longest signals are the pure CF signal which typically last 13.3 ms but can go as long as 17 ms.[14] 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.[14] 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.[7] The second type has the CF starting at a frequency of 60 kHz and then falls for more than a single octave.[7]
For females, pregnancy occurs from September until January, and lactation starts in November and continues until April.[5] Only one young is born each gestation.[7] Male bats mostly breed autumn and winter.[7] Young bats stay in the roosts for one month and are then capable of flight.[7] Both the male and female care for the young.[7]
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.[1]
The greater bulldog bat or fisherman bat (Noctilio leporinus) is a species of fishing bat native to Latin America (Spanish: murciélago pescador; Portuguese: morcego-pescador). The bat 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.
