Hipposideros gigas, the giant leaf-nosed bat, is found in Africa south of the Sahara Desert. It formerly was considered a subspecies of H. commersoni, but is now recognized as a distinct species. Like other members of Hipposideridae, these bats specialize in hunting insects in complex habitats (in and near vegetation). They have an unusual, highly specialized echolocation system that takes advantage of the Doppler shift to separate emitted pulses (calls) and returning echoes in frequency rather than in time.
These bats simultaneously emit long, constant frequency calls and listen to returning echoes, and analyze the resulting auditory data to build a complex, dynamic auditory map of their environment. An anatomical feature associated with use of Doppler shift echolocation is an extremely large cochlea, in which the basal turn is tuned to be especially sensitive to the frequency of returning echoes, which are lower frequency than the calls emitted by the bat. The complex leaf-like foliations on the face around the nose are thought to function somehow in emission of echolocation calls (which are emitted through the nose in this clade), but the details of how this might work remain unclear.
About the Species
A whole preserved specimen of Hipposideros gigas was scanned on 12 February 2003. It is part of the American Museum of Natural History Mammalogy Collections (AMNH 268379). The specimen was made available for scanning by Dr. Nancy Simmons of the American Museum of Natural History. Funding for scanning was provided by a National Science Foundation grant (DEB-9873663) to Dr. Simmons, and funding for scanning and image processing was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Timothy Rowe of the Department of Geological Sciences, The University of Texas at Austin.
About this Specimen
The specimen was scanned by Matthew Colbert on 10 March 2003 along the coronal axis for a total of 321 slices, each slice 0.0179 mm thick with an interslice spacing of 0.0781 mm.