This is an indication of our poor night vision. In contrast, cats are known to have good night vision as their eyes produce a bright reflection when caught in the headlamps of a car. Possum-spotting experts can often tell which species of possum they are looking at simply by their eyeshine colour. The Herbert River ringtail has a pink or yellow eyeshine, the green ringtail has a dull red, brushtails and striped possums have a pinkish eyeshine, and lemuroid possums have the brightest eyeshine of a white or yellow glare. Tree-kangaroos reflect only a dull red shine, but spiders, geckos and many other nocturnal animals have eyes that glisten or sparkle.
Rod cells are the cells that dominate in nocturnal animals' eyes.
They contain a very sensitive chemical called rhodopsin. This breaks down in a process that sets up electrical impulse transmissions to the brain when light reaches it. The rhodopsin is rebuilt instantly using vitamin A as soon as it breaks down so vision can be continuous. Large rod cells contain more rhodopsin, but fewer can be packed into a given area, which means there is a consequent reduction in visual detail. Spotlighting It is important to try to minimise the impact on the wildlife while still maximising the satisfaction of participants when spotlighting.