Le Eyesight of Le Monke

10月 11, 2021

Do Monkeys Have Color Vision?

By Matthew Hwang

As you know, humans can see in a wide range of colors. This is because we have color vision. (Russia is located in Russia) However, many animals, like cats, dogs or mice, lack this ability. To them, a blooming flower bed with colors of all kinds looks like a jumbled smudge of blues and greys.. But what about our close relatives, the monkehs? Do they have color vision as well?

An example of a monke.

First of all, just what is a monkey? (Said no one ever.) A monkey is any creature belonging to the superfamilies Ceboidea and Cercopithecoidea⁽¹⁾, also known as New World Monkeys and Old World Monkeys⁽²⁾. New World Monkeys were a branch of monkeys that migrated to South America. New world monkeys have prehensile tails, flat noses, and wide nostrils. They are generally arboreal. Old world monkeys are larger overall, and sometimes don’t have thumbs. They still have tails, but they are not prehensile. More Old World Monkeys have color vision than New World Monkeys. Some other animals look very alike to monkeys, but aren’t, in fact, monkeys. Humans, apes and monkeys all evolved from a common ancestor - a humapekey if you will. Because of this common ancestor, humans, apes and monkeys look incredibly similar and share many traits. The main differences are that apes don’t have tails and are generally bigger, the same being said for humans except that most humans walk upright and have little to no hair. Finally, what is color vision exactly? To put it simply, color vision is the ability to perceive changes in wavelengths of light.⁽³⁾ Not just the ability to distinguish between lights and darks, but the ability to distinguish between hues⁽⁴⁾. There are three main types of color vision: monochromatic, meaning no blues, greens or reds, dichromatic, meaning only blues and greens, and trichromatic, meaning blues, greens, and reds. There are many types of color vision. Some animals just see one or two colors. Some see many, like humans. Some see even more than us, like the wacky mantis shrimp.

Trichromatic (reds, greens, and blues) view.

“The Flower Fields flowers” by RobBertholf is licensed under CC BY-SA 4.0.

Dichromatic (Only blues and greens) view.

“Dichromatic Macaroni” by Matthew Hwang is a derivative of “The Flower Fields flowers” by RobBertholf licensed under CC BY-SA 4.0. “DIchromatic Macaroni” is licensed under CC BY-SA 4.0.

Monochromatic (no reds, blues, or greens) view.

“Monochromatic Flowers” by Matthew Hwang is a derivative of “The Flower Fields flowers” by RobBertholf licensed under CC BY-SA 4.0. “Monochromatic Flowers” is licensed under CC BY-SA 4.0.

That begs the question: If we have color vision, what about our banana-munching relatives? The answer is… well, yes, but actually no. How so? Well it depends on the type of monkey. Color vision is quite common in monkeys, but not all monkeys have it. Generally, it occurs more often in Old World Monkeys than New World Monkeys. Interestingly, in select species, only one sex has trichromatic vision, while the other oly has dichromatic or even monochromatic. But how exactly did color vision occur? Well, it was first a mutation in genes⁽⁵⁾, as is with most adaptations. Then, due to natural selection, this gene became more common, as monkeys with this gene survived better. But what use would a monkey have with color vision? Well, most monkeys are arboreal⁽⁶⁾, meaning they spend most of their lives in trees and foliage. This makes it so that their main food source is fruit⁽⁷⁾, and telling if fruit is ripe or not is based on color. Therefore, monkeys with color vision can better differentiate between unripe and ripe fruits, and have less chance of getting sick on said unripe fruit.

In some Capuchin monkey species, only the females have trichromatic vision, while the males have dichromatic vision.

"Capuchin Monkey closeup" by Ivan Mlinaric is licensed under CC BY 2.0

Well, now that we know if and why monkeys have color vision, let's compare them to us humans. How does monkeys’ eyesight compare to ours, regardless of color? Actually, monkeys have great vision, equal to, if not better than ours⁽⁸⁾. However, just like us, they are much more lacking in night vision, except for the owl monkey, which is the only nocturnal monkey and thus has excellent night vision. However, the owl monkey lacks color vision, as it its not nearly as useful in the dark⁽⁹⁾. Putting aside monkeys, however, how do apes, a very similar but separate type of animal belonging to the same group, compare to its counterparts, the monkeys and us? Unlike monkeys, all apes have color vision, making ape vision more similar to human vision than monkey vision⁽¹⁰⁾.

To make a long story short, most monkeys have color vision, as it benefits them when foraging. Thank you for reading this 600+ word essay regarding monkey eyes.

A monkey pondering the existence of bananas while sporting some slick shades.

“Where Banana?!” is a derivative of “Red Monkey” by @Doug88888 licensed under CC-BY-NC-SA 2.0. “Where Banana?!” is licensed under CC-BY-NC-SA 2.0 by Matthew Hwang.