Tigers Are Known For Their Fiery Fur, But Why Are They Orange?
Tigers are known for their striking orange fur lined with dark stripes. Orange has always seemed like a bold color for an animal to be. It stands out in most environments, which means it’s easy to spot.
The fiery orange coat of tigers might seem flashy to us, but it actually serves a vital purpose. It helps them blend seamlessly into their environment.
For ambush predators like tigers, it’s important that they’re able to remain invisible to their prey; otherwise, they will have to go without dinner.
To us, the color orange is super visible because humans have something called trichromatic color vision. When light enters the eye, it hits the retina, a thin layer toward the back of the eye. The retina uses two types of light receptors to process light—rods and cones.
Rods sense differences in light and darkness. They are mostly used in dim lighting. Cones are responsible for color perception. Most humans have three types of cones for red, green, and blue.
We can see three primary colors and their combinations, which is why our vision is called trichromatic. Apes and some monkeys have this style of vision as well.
However, most terrestrial mammals like cats, dogs, deer, and horses have dichromatic color vision. Their retinas only contain cones for two colors—blue and green.
Humans who have only blue and green cones cannot tell the difference between red and green shades, and they are considered color blind. The same goes for animals with dichromatic vision.
The tiger’s main prey is deer. But since deer have dichromatic vision, they do not see the wildcat as orange. Instead, the tiger appears to be green so it can camouflage itself among the green grass and bushes.
Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox
If that’s the case, then why don’t tigers just have green fur? Well, evolution just doesn’t work that way.
“In essence, it is easier to produce browns and oranges because of the biomolecular structure of the makeup of the animal,” said John Fennell, a lecturer in animal sensing and biometrics at Bristol Veterinary School in the United Kingdom.
“In fact, the only recognizably green [mammal] is a sloth, and its fur isn’t actually green. That’s an alga that grows in its fur. And as far as I’m aware, there are no green furry animals.”
Fennell has employed artificial intelligence to determine the most effective camouflage for a dichromat. The project confirmed that it took a lot longer for dichromats to spot a tiger than trichromats.
Evolution generally favors traits that enhance survival, so it would make sense for prey animals to develop the ability to detect orange.
But there is no evolutionary pressure for deer to become trichromatic. This is likely because the tiger is also a dichromat and does not know that it is orange.
“So the evolutionary arms race really doesn’t exist for that color, as such,” said Fennell. “It’s just that the tiger has evolved over the sweep of evolution to have a coloring, a camouflage system, which protects it very well in its jungle setting.”
More About:Animals
Read This Next
