Evolution of auditory sensitivity among strepsirhine primates

Abstract

Hearing is a crucial element of primate behavior and ecology. Beginning in 1969, traditional behavioral testing methods produced comparable audiograms for five strepsirhine taxa. Variation in this relatively small data set can be explained in part by head size, but relationships with social behavior and ecology have been elusive. Recently, with the use of auditory brainstem response (ABR) methods, standardized audiograms have been published for eleven strepsirhine species. Within this data set, social complexity explains a signi ficant amount of the variation in auditory sensitivity, possibly because sociality favored an enhanced ability to detect conspeci fic vocalizations such as high frequency alarm calls. These findings shed light on the comparative biology of primate hearing and enable a reconstruction of the ancestral strepsirhine audiogram.