Perhaps best known for its habit of hunting fish, giving it the alternative name of ‘fishing bat’, the greater bulldog bat typically forages over water, using echolocation to detect the ripples made by fish as they disturb the water’s surface (2) (3) (4) (5) (6). The long legs and long, sharp claws are used to skim the water and snatch up prey from just below the surface. The prey is then quickly transferred to the mouth, with the tail membrane brought up under the body to prevent it being dropped, and is either eaten in flight or stored temporarily in cheek pouches and carried to a perch to be consumed (2) (4) (5) (6) (7). The greater bulldog bat may consume as many as 30 or 40 fish in a night, capturing prey up to 10 centimetres in length, and will also take insects, shrimps, crabs and scorpions (2) (3) (4) (6) (7). As well as from water (including the sea), prey is also sometimes taken from the ground or in the air (4) (6), although insects caught in the air are captured in the wing or tail membranes rather than with the feet (2) (4). If knocked into water, this species is able to swim well, and can even take off from the water (2) (7).
The greater bulldog bat may forage in small groups of around 5 to 15 individuals (1) (2) (6), and during the day will roost in colonies that sometimes number into the hundreds (1) (4) (5) (9). Within the roost, the bats cluster into small ‘harem’ groups, typically consisting of two to nine adult females and a single adult male. Bachelor males roost separately, either alone or in small groups (4) (9) (10). The harems are quite stable in composition, often occupying the same roost site over many years, but the group is usually taken over by a new male every two years or so (4) (10). Interestingly, females from the same roost group often forage together, while males usually forage alone (4) (10).
The greater bulldog bat usually gives birth once a year, to a single young at a time, but in some areas breeding may occur twice in the same year (4) (5). The breeding season varies with location, usually coinciding with peak food availability. Pregnancies have been reported between September and January in some regions, with young suckled in November to April (2), while others report breeding to begin in November and December, with births occurring from late April to June (5). Females may form ‘nursery colonies’, gathering together to give birth (2) (8). The young bats fly for the first time at around 1 to 2 months old (4) (5), and the species may live for up to 11 years in captivity (2) (4).