Noctilio leporinus, Linnaeus, 1758

Don E. Wilson & Russell A. Mittermeier, 2019, Noctilionidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 404-411 : 410-411

1.

Greater Bulldog Bat

Noctilio leporinus

French: Grand Noctilion / German: Grofes Hasenmaul / Spanish: Noctilio grande

Other common names: Fisherman Bat

Taxonomy. Vespertilio leporinus Linnaeus, 1758 ,

“America.” Restricted by O. Thomas in 1911 to “ Surinam [= Suriname].”

Taxonomy of N. leporinus has been stable for a long time, and in 1973, it was clarified that its taxonomy is quite simple. Morerecent work based on DNA sequencing of mitochondrial (control region) and nuclear (RAG2) genetic material yielded a relatively homogeneous phylogenetic landscape with low genetic diversity that seemedto indicate that the northern subspecies was valid. In South America, N. leporinus might be represented by only one other subspecies, but additional research is needed. Three subspecies recognized.

Subspecies and Distribution.

N.l.leporinusLinnaeus,1758—theGuianas,AmazonBasin,andmostofBrazil.

N.l.mastivusVahl,1797—W&SMexico,CentralAmerica,WestIndies,N,W&EColombia,Venezuela,WEcuador,andextremeNWPeru.

N. l. rufescens Olfers, 1818 — E Bolivia, Paraguay, N Argentina, and S Brazil.

Descriptive notes. Head—body 82-100 mm, tail 23-28 mm, ear 28-30 mm, hindfoot 25-34 mm, forearm 81-87 mm; weight 50-90 g. The Greater Bulldog Batis relatively large compared with other bats that coexist with it. Furis extremelyshort, almost velvety, andstiff. Colorvaries from light brown usually in females to rich reddish brown or even bright yellow in males. Thereis a pale, almost white thin line along dorsum from nape to rump. Venteris paler. Hindclaws are extremely elongated, sharp, recurved, and used to grabfish when feet are dipped into water. Interfemoral membraneis very wide androbust. Faceis verydistinctive, with naked cheeks and snout andslit upper lip. Ears are separate, narrow, and slightly elongated.

Habitat. Dry and humid tropical forests, small coastal lagoons, mangroves, and other tropical vegetation types, with large trees and standing or slow-flowing waterin wide lakes, slow-flowing rivers, or estuaries from sea level to elevations of ¢. 500 m. The Greater Bulldog Bat roosts in hollowtrees, although some have been reportedin caves and rock crevices and occasionally human structures such as bridges.

Food and Feeding. Greater Bulldog Bats are adaptedto feed on fish that they capture directly from the watersurface. Fresh andsaltwaterfish dominate diets, but insects are also eaten, sometimes copiously. In adequate conditions, it is quite a spectacle to watch small groups of Greater Bulldog Bats raking the water surface with their claws over and over. One study showed that as much as 80% of the diet can be insects. Other prey included shrimp, crabs, and scorpions. Greater Bulldog Bats have large cheek pouches that they use to store partially chewed prey; they forage until cheek pouches are full and then finely chew and swallow prey items. When foraging over water, they use three forms offishing: high search flight, low search flight, and random rake. In high search flight, they emit long (13-3-17 milliseconds) pulses and fly 20-50 cm above the water surface, point-dipping their hindclaws when a food item is detected. In low search flight, they emit shorter pulses (c.5:6 milliseconds) and fly only 2-4 cm above the water and also point-dip their hindclaws when prey is detected. During random rake, they echolocate as during high search flight but dip their hindclaws in the water for up to 10 m. Random rake is mostly used in the presence of copious jumping fish, and they can catch a fish every 50-200 passes.

Breeding. Female Greater Bulldog Bats have a single embryo per pregnancy. One to two seasonal peaks in births occur, depending on the area. Often the first birth peak coincides with the onset of the rainy season, varying geographically from April to June, and the second peak, usually smaller than the first, occurs toward the end of the rainy season. Nevertheless, pregnant and lactating females and males with scrotal testes have been reported in every month of the year, but individual females have a single pregnancy per year. Although data are limited, gestation seemsto last c.5 months. Testes of males grow and produce sperm seasonally. Males have two ancillary skin sacks in the genital area that might have hormonal or glandular function.

Activity patterns. Greater Bulldog Bats are nocturnal, generally leaving the roost within two hours after sunset. In Puerto Rico between November and January, they left the roost within an hour after sunset, but in August, they left an hour later with no apparent reason for the change. Most activity occurs before midnight. On cold nights with temperatures below 12°C, they did not leave the roost. Groups of bats seem to leave the roost together but do not return together. When female members of the same group left the roost, they lingered in its vicinity until other members of the group exited the roost, and then they all flew together toward foraging areas, within 5 m of each other.

Movements, Home range and Social organization. Despite their large size and relatively open foraging habitat, few studies have been conducted to follow movements of Greater Bulldog Bats. They have relatively small home ranges, and flying distances to forage are less than 1 km from the roost. Foraging females belonging to the same group had overlapping home ranges, with radio-locations indistinguishable from one another, and females returned to the same foraging area night after night, even in different years. Males forage separately from females. A study in Puerto Rico showed that colonies are usually formed by groups of 3-10 females and a single male, plus additional groups of 1-3 bachelor males, but this structure can be repeated more than once in a roost. Social groups are very cohesive, and when a group of females moves to a different roost, they do it together and also with the resident male of the harem. These groups remain as stable units for at least two years. Females and males within a group mark themselves periodically with secretions from subaxial glands. Females rub their heads under wings of other females; males mark themselves the same way. Females also rub their chins or heads against heads of other females within the same social group inside a roost but never against members of other groups. Some females occasionally move temporally to join other social groups in the roost, and during those occasions, all other females smell a visitor’s wings and head for about a minute; the visitor eventually returns to the original group.

Status and Conservation. Classified as Least Concern on The IUCN Red List. No country across its distribution lists the Greater Bulldog Bat as threatened or endangered. If habitat is in good condition, their populations are stable. It is likely, however, that removal or disturbance of roosts, such as large hollow trees or caves, can have negative effects on Greater Bulldog Bats.

Bibliography. Bordignon (2006), Bordignon & Franca (2016), Bork (2006), Brooke (1994, 1997), Davis (1973), Hood & Jones (1984), Mares et al. (1981), Pavan et al. (2013), Schnitzler et al. (1994), Thomas (1911a), Zortéa & Aguiar (2001).

Figures

Plate 31 Species Accounts

Subspecies and Distribution. N.l.leporinusLinnaeus,1758—theGuianas,AmazonBasin,andmostofBrazil. N.l.mastivusVahl,1797—W&SMexico,CentralAmerica,WestIndies,N,W&EColombia,Venezuela,WEcuador,andextremeNWPeru. N. l. rufescens Olfers, 1818 — E Bolivia , Paraguay , N Argentina , and S Brazil .