Scotopic threshold responses to infrared irradiation in cats

Abstract

Infrared (IR) irradiation is frequently used in ophthalmological diagnosis and treatment. It has been used to selectively stimulate photodiode-based retinal prostheses to prove their function. Data concerning the natural IR-sensitivity of the retina are contradictory. In our experiments in dark-adapted cats an IR-laser (826 nm) and IR emitting diodes (875 nm) elicited clear scotopic threshold responses. Comparison of the two lasers (IR and a visible laser at 670 nm) using Lambs template and our experimental data revealed very similar differences in retinal sensitivity (4.28 and 3.94+/-0.29 log units, respectively). The fact that the cat retina is sensitive to IR-irradiation under certain conditions has important implications in interpreting the results from retinal prostheses and rewards further attention in its use in many ophthalmological applications.

Camera Traps Can Be Heard and Seen by Animals

“…Cats appear to detect the presence of camera traps more than other animals (Meek Unpub data; Ballard Unpub data), which is probably due to their retina sensitivity at 826 nm [49] and total vision field of view being 287° with binocular over lap of 130° [37] . This peripheral view combined with the very high sensitivity to infrared light at the higher end of the near infrared spectrum would make cats more than capable of easily detecting camera trap flashes; especially in models with light emissions below 800 nm (see Fig.…”

Are we getting the full picture? Animal responses to camera traps and implications for predator studies

“…; Heffner and Heffner ) and vision (Ewer ; Gekeler et al. ). However, there were many cases where an animal displayed a negative response when they were within 5–10 m of the camera trap and were startled without looking at the camera trap.…”

“…The responses of feral cats to camera traps in day-andnight events were indicative of an animal with acute hearing (Peterson et al 1969;Heffner and Heffner 1985) and vision (Ewer 1998;Gekeler et al 2006). However, there were many cases where an animal displayed a negative response when they were within 5-10 m of the camera trap and were startled without looking at the camera trap.…”