We thought it was worth sharing because the article has a wealth of information on not only the auditory and visual ranges of predatory animals, but also on the auditory, infrared, and ultrasonic outputs of trail cams produced in 2014.
Please note the authors did not test actual reactions by animals to the cameras. They measured the visual and auditory outputs of the cameras then compared those to the known visual and auditory ranges of the animals.
Here are a just a few of the interesting things we took away from the article:
- Trails cams seem to have their own unique frequency signature.
- All the cameras emitted ultrasonic outputs when their batteries were low.
- The Reconyx HC600 sound outputs fall within the hearing range of most of the species studied.
- Camera traps that are advertised as “no glow” or “black ops” still use infrared, but with wavelengths above 850 nm which is still within the visual range of some animals.
- Some humans can see infrared light. One of the authors was able to see a faint red glow from the Reconyx HC600 in absolute darkness.
- Cats have a high sensitivity to infrared light and appear to detect trail cams more often than other predators.
- The output sounds of a trail cam drops 6 dB every meter away from it.
- There are several downloadable charts from the study. One shows the auditory ranges of many predators including humans.