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. References External links 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