I have been using IR trail cams for over two years now and foxes, like cats, DO see the IR light. Initially I could not understand WHY the foxes were hopping around -almost startled. I then noted the local cats were also doing this. To see what was making them so jumpy I placed one cam facing toward the other camera.

Next day I had my answer. The second camera recorded a big flash of light (or ten second light when a video clip was recording). I had no idea just how bright these lights were.

Toprove the point the foxes were cautiously looking at the camera, approaching it nervously and when I put the camera in a different position the surprise of the flash made one fox jump up in surprised shock.

The cats got used to the cameras quickly and unbelievably played with the light or, rather, with the camera to set off the light, Any new cats passing through took the defensive stance when the light came on. The cat next door to me would even cross the garden to deliberately trigger the camera.

Hedgehogs also clearly see the flash. Being more belligerent I have them on video quickly approaching and head-butting the camera and on one occasion two large hogs actually attacked the camera itself.

I then began checking other cam video clips posted to fox groups -same thing -even the intertest in them displayed by hedgehogs.

This led me to realise that these are NOT "unobtrusive" -looking at many trail cams out in the wild it is clear that deer can see IR light and there are even photos of groups of deer staring straight at the cameras and the cameras do not "click" or make sounds. Many other nocturnal animals also look at the cameras.

Just seeing the reactions and moving the cameras around showed me that cats, foxes and hedgehogs CAN see the light but after a couple weeks of checking other peoples trail cam footage and looking at animal reactions to the cameras in forests and jungles it was quite clear the light may be invisible to humans but not animals.