The Collaborative International Dictionary
Bulldog \Bull"dog`\, a. Characteristic of, or like, a bulldog; stubborn; as, bulldog courage; bulldog tenacity.
Bulldog bat (Zo'94l.), a bat of the genus Nyctinomus; -- so called from the shape of its face.
Wiktionary
n. Any of various bats of the family Noctilionidae.
Wikipedia
The bat family Noctilionidae, commonly known as bulldog bats or fisherman bats, is represented by two species, the greater and the lesser bulldog bats. They are found near water, from Mexico to Argentina and also in the Caribbean islands. The naked bulldog bat ( Cheiromeles torquatus) does not belong to this family, but to the family Molossidae, the free-tailed bats.
The bulldog bats have orange to brown fur, and range in head-body length from 7 to 14 cm. They have relatively long legs, large feet exceptionally so in the case of the greater bulldog bat and strong claws.Their wings are long and narrow and their ears are large and funnel shaped. Unusual among bats, they have cheek-pouches for storing food. They also have full lips divided by a fold of skin giving a 'hare lip' look which together with the cheek pouches gives them their bulldog-like appearance. The species of lesser bulldog bats are insectivorous and whilst the greater bulldog bats also eat insects their chief food is fish. They use their echolocation to pinpoint the ripples they make on the surfaces of water.
The greater bulldog bat trawls the water with its long, curved talons approximately 2–3 cm below the surface. It makes sweeps of between 30 cm and 3 m before ascending and turning to make a return sweep. In a single night, the bat may catch 20-30 small fish in this way.