NEW WINDOWS ON THE WORLD: SENSORY MODALITIES BEYOND HUMAN PERCEPTION

Abstract

This chapter discusses the sensory modalities beyond human perception. Sensory information can be either chemical or physical in nature. Chemical stimuli are familiar to humans through olfaction and taste, but many physical stimuli are beyond human perception. Sound frequencies beyond the range of hearing are important to many animals, both at very high frequencies and, more unexpectedly, at very low frequencies. For many animals, the ability to perceive light extends into the ultraviolet part of the spectrum to which humans are blind. The polarization of the light is perceived and provides essential information for the orientation of many animals, not only insects but also many vertebrates. Sensitivity to infrasound may be very important to the birds for natural infrasounds originate from many sources, including thunderstorms, earthquakes, jet streams, and wind over mountain ranges. The attenuation of sound is inversely related to the square of the wavelength and infrasounds can, therefore, travel over long distances and can be detected at hundreds or even thousands of kilometers from their source.