ELECTROPHYSIOLOGICAL MEASUREMENTS OF SPECTRAL MECHANISMS IN THE RETINAS OF 2 CERVIDS - WHITE-TAILED DEER (ODOCOILEUS-VIRGINIANUS) AND FALLOW DEER (DAMA-DAMA)

Electroretinogram (ERG) flicker photometry was used to study the spect ral mechanisms in the retinas of white-tailed deer (Odocoileus virgini anus) and fallow deer (Dama dama). In addition to having a rod pigment with maximum sensitivity (lambda(max)) of about 497 nm, both species appear to have two classes of photopic receptors. They share in common a short-wavelength-sensitive cone mechanism having lambda(max) in the region of 450-460 nm. Each also has a cone having peak sensitivity in the middle wavelengths, but these differ slightly for the two species . In white-tailed deer the lambda(max) of this cone is about 537 nm; f or the fallow deer the average lambda(max) value for this mechanism wa s 542 nm. Deer resemble other ungulates and many other types of mammal in having two classes of cone pigment and, thus, the requisite retina l basis for dichromatic color vision.