Morphological Adaptations of the Ear in the Rodent Family Heteromyidae

Abstract

Middle and inner ear structure and auditory sensitivity have been studied in all five genera of the rodent family Heteromyidae. In the most xericc genera (Dipodomys and Microdipodops) the middle ears are greatly inflated the tympano-ossicular system very efficient the organ of Corti extremely modified and low-frequency sensitivity extremely acute. In the most mesic genera (Heteromys and Liomys) the middle and inner ears show few modifications and the low frequency sensitivity is rather poor. Perognathus is intermediate in habitat structure, and low frequency sensitivity. Experimental data demonstrate that the low frequency sensitivity in Dipodomys is adaptive in predator avoidance.