COMPARATIVE-STUDY OF SOUND LOCALIZATION AND ITS ANATOMICAL CORRELATESIN MAMMALS

One of the fundamental features of hearing is the ability to localize the sources of sounds, particularly brief sounds, which may warn of ne arby animals. Yet not all mammals localize sound equally well with thr eshold acuity ranging from about 1 degrees for elephants and humans to mure than 25 degrees for gerbils and horses and a near absence of loc alization in some subterranean species. During the past decade evidenc e has accumulated that this variation cannot be accounted for simply b y the availability of the physical cues for locus, Nor does it appear to be a function of an animal's lifestyle. Rather should-localization acuity in mammals appears to be a function of the precision required o f the visual orienting response to sound. Thus the neural integration of hearing and vision in cortex, as well as in multimodal subcortical structures. is a reflection of their behavioral integration and evolut ionary coupling.