Colour Vision in Animals

  

It will come as no surprise that an animal's view of the world is different to our own, but what isn't so clear is exactly what they see. A recent exhibition at the Royal Society showed images that illustrates what our pets and other animals see when they look at each other and when they look at us. 

The fascinating insight shows the latest research into the colour vision of animals, many of which can see ultraviolet, or colours that we can't see, making their world view completely different to ours. 

Birds, for example, can see ultraviolet so a peacock looking at a potential mate would not see the beautiful rainbow of greens and blues that we behold, but a plainer yet more brightly coloured display of plumage. 

Birds have four types of cone cells in their eyes called photoreceptors (humans have three), and can see many more colours than we can. They can also see ultraviolet, which means that the 'eye' markings in a peacock's tail features looks sharper.

Purple haze: Using the ultraviolet recepters in its eyes the peacock would see a mating feather display more like the example in the above photograph.

Understanding how animals see the world could be key to understanding their behaviour. 

Animal colouration provides some of the most striking examples of evolution by natural and sexual selection. But animal colours did not evolve for our benefit; the impressive array of animal colours that we see (and can’t see) in the natural world allows animals to communicate with each other, to attract mates and to avoid predators. 

Dr Tom Pike, Senior Lecturer from Lincoln University’s School of Life Sciences, said: ‘We rely overwhelmingly on colour vision in our everyday lives, and tend to assume that what we see represents the limits of the visual world. 

'However, colour vision in animals, and their resultant perception of the visual world, often differs considerably from our own. The eyes of cuttlefish evolved separately from humans and are completely different from ours - they can't see colours, but can discern the polarisation of light, which lets them pick out contrasts better.  The colourful spots are designed to fend off predators - what the butterflies themselves see is quite different ‘Many, for example, can see ultraviolet light, some can see polarised light, and a good number can see many more colours than we can,' says Pike. 

'Having said that, certain animals see far fewer colours than us – something that anyone who is colour blind can sympathise with.' 

‘Because animal colours evolved for the benefit of animal - and not human - eyes, understanding the visual world from an animal’s point of view can explain why some animals are bright while others are dull. Some are highly patterned and others plain. This allows us not only to shed exciting new light on the animal colours we can see, but also to understand the importance of colours that we can’t.’