According to a new study. cats, dogs, and other mammals are thought to see in ultraviolet light, which opens up a whole different world than the one we see.
UV light is the wave length beyond the visible light from red to violet that humans can see. Humans have a lens that blocks UV from reaching the retina. It was previously thought that most mammals have lenses similar to humans.
What purpose does being able to see UV light serve for animals such as reindeer, rodents, and other mammals?
It allows reindeer to see polar bears, for example, which would be invisible in regular light because they blend in with the snow. UV light also allows mammals to see urine trails. This would be helpful for prey animals, such as cats and dogs, to find food in the wild.