How animals see the world?
Šimon Petránek
We all, humans, see the world full of colours, however, our sight is as unique as any other organism, so it is clear that animals, like cat, dog or snail see the world differently than human beings. Haven´t you always wondered what your pet sees?
The answer is adaptation. It highly depends whether the animal is nocturnal or not, also if it lives in the water, or is terrestrial. It also has to adapt to their lifestyle.
Human
Dog vision
Whereas human eyes contain three types of colour-detecting cells, called cones, dogs have just two. Their cone cells are specialised for picking up yellow and blue-to-ultraviolet light. Each cone type contains a pigment sensitive to particular wavelengths of light.
The range of colours an animal sees depends on the combination of colour-sensitive pigments in their eye and the processing by the brain.
With fewer cone types, dogs can't distinguish between as many colours as we can.
A Dog
Garden snail vision
Although the eyes of garden snails can't focus or see colour, they would just about be able to make out this other snail moving past, or a predator approaching.
The snail's ability to discern different intensities of light helps it navigate towards dark places.
Human
Human
Gecko vision
Humans don't see colours very well, or even at all, in low light. This is because our cone cells function best in relatively bright light.
Other cells in our eyes, called rod cells, help us see in dim light. But because rod cells only have a single light-sensitive pigment, at night we see in shades of grey.
Geckos, on the other hand, have excellent colour vision at night - a useful advantage for a nocturnal hunter. Their eyes have evolved to be up to 350 times more sensitive to colour at night than ours.
A Gecko
A Garden snail