The visible spectrum of light is a very small portion of the electromagnetic spectrum and encompasses the wavelengths from about 400 to 750 nm (Figure 1). Illumination with infrared light in the wavelengths of 800-900 nm (beyond the visible spectrum) does not require specialized camera equipment and is the principle behind night security photography. Humans and most mammals cannot see light at these wavelengths, but the camera can when IR light is provided.
The use of security cameras on mink ranches has raised the question about the effects of infrared light, which is used as a light source for these cameras, on mink reproduction. Anecdotal information suggests that some ranchers may be deciding not to install cameras because of their concern that infrared light may adversely affect reproduction. A search of the scientific literature indicates that essentially no research on this question has been conducted, with the exception of one rodent study, which indicated slight differences in reproduction between infrared exposed and control mice and a significant increase in survival rate in the infrared exposed group compared to the control group (Udagawa and Nagasawa, 2000).
This project was undertaken to determine if ranchers need to be concerned about adverse reproductive effects associated with the use of infrared lights near their animals. If infrared light does have an effect on reproduction/survival, then measures can be taken to shield animals from exposure.