Orange Fur Helps Tigers Prey on Colour-Blind Animals like Deer, Shows Research

Orange fur helps tigers blend perfectly in their surroundings and prey upon color-blind animals such as deer, researchers have found.

Humans with normal colour vision can see red, blue and green colours.

But new research using computer simulations of what the big cats look to their prey like deer shows a different picture, Daily Mail reported.

Deer can only pick up blue and green light, making them effectively colour blind to red.

This means the “tigers’ orange colouration look green to them, allowing them to blend perfectly into the background.

Dr Fennell at the University of Bristol said that by simulating what the world looks like to ‘dichromats’, animals who cannot detect the difference between red and green, “we also identify the optimum colours for concealment and visibility.”

“Consider the coat of a tiger (Felis tigris); it has fur that appears orange to a trichromat observer rather than some shade of green, though the latter should be more appropriate camouflage for an ambush hunter in forests,” Dr Fennell wrote in the Royal Society Journal Interface.

“However, as illustrated, when viewed as a dichromat, the tiger’s colour is very effective.”

Dr Fennell tested the theory on people, by screening images in which a red object was inserted in two backdrops.

One was of temperate forest - for which pictures of Leigh Woods in North Somerset, and semi-arid conditions, in the Tabernas Desert in Almeria in Spain.

The doctor and his colleagues then measured how quickly the observers detected the sphere against each backdrop in images reproduced to simulate three-colour vision, and two colour vision.

Observers were much quicker at detecting the images with three colours in both scenarios.

Dr Fennell and colleagues said that mammals are not able to produce green fur as that would “require a significant change to mammalian biochemistry.”

The orange colour in a tiger’s coat is produced by a chemical called pheomelanin.

Dr Fennell said that why deer never evolved trichromatic vision, which would have helped them to spot the tigers better and stop getting eaten, was an “open question.”