Prince.Skeletor
Don’t Be Like He-Man
I never knew this
Why would they have this evolutionarily?
What purpose does it serve?
An accentuation in the jungle is a target.
Hamadryas Baboon Butt
Many members of the baboon family, like this hamadryas baboon, have prominent buttocks. Unlike many other primate species, the baboons are largely terrestrial, living on the ground in fields and deserts rather than up in the trees. They, like us humans, have the need for some kind of padding on the rear end so they can sit down comfortably for long periods of time. These baboons have what can best be described as calloused, puffy skin on the buttocks; not super attractive, at least to us, but very effective for sitting, which is the baboon’s favorite position.
Celebes Crested Macaque Butt
The Celebes crested macaque, also known as the crested black macaque, is perhaps best known for its fantastic selfie skills. But it’s also an interesting creature, butt-wise. Both the males and females of the species are highly promiscuous, and the female macaque uses its outrageously swollen rear end to indicate that it’s receptive.
Mandrill Butt
And that brings us to the primate with the most colorful buttocks of all: the mandrill. The mandrill is the largest non-ape primate, and also arguably the most colorful, with a trademark bright red and blue nose and a frankly gorgeous rainbow-colored butt. These are secondary sexual characteristics, present in both sexes but much more vibrant in males. Just look at that butt!
To answer these questions, it is important to first understand how light interacts with living stuff, which we call biological tissue. Light is a collection of little packets of energy, called photons, that whiz through the air. Photons come in all different colors, and when these colors are all together, we see white light (like sunlight or light from a light bulb). But photons of different colors act differently when they enter biological tissue.
You can think of a photon as a drunk person walking through a forest. The drunk person enters the forest and walks into a tree, D’oh!, changes direction (scatters) and walks another short distance and into another tree, D’oh! D’oh! D’oh! D’oh! …. and before you know it the drunk person exits the forest in a random place going a random direction.
When photons enter the skin, it is just like the drunk person walking in the forest. Photons bounce off collagen fibers (instead of trees) and emerge from the skin at a random place. In optics, we call this diffuse reflection. A visual representation of diffuse reflection is when a LASER beam hits the surface of milk, giving off a “glow ball” around the LASER spot. (You can also catch my personal demonstration HERE).
Before it gets detected by your eye, a single photon that penetrates a biological tissue (like skin) will randomly scatter within the tissue many times. But it is important to consider that skin is more complex than the forest analogy. Skin is composed of many layers and contains pigments such as melanin, and this affects how photons scatter. This added complexity is the secret to the blue monkey butt.
To understand how photons move through a complex tissue like skin, lets compare a red photon with a blue photon as it hits two tissue layers. Tissue “A” is on top, and Tissue “B” is underneath. If layers A and B were both white (like milk), they would reflect red and blue photons equally and you would see both colors.
But in real skin, the top layer (Tissue A) has only a little melanin, while the next layer of skin (Tissue B) can contain a lot of melanin, which is important because melanin absorbs light, “killing” any photons that encounter it!
In the picture above, both the red and blue photons bounce (scatter) 4 times while they are penetrating the skin. But because the red photons travel a longer distance in between scattering events, they manage to penetrate both layers of skin. The melanin in Tissue B absorbs the red photon so it can’t leave the skin and reach your eye.
In contrast, the blue photons take very short steps in between their scattering events, and they don’t penetrate very deep. They do not make it past Tissue A before they emerge and hit your eye.
A baboon’s butt tissue is arranged somewhat like the illustration above so that blue photons are reflected and all of the other photons (like the red ones) are absorbed. Only the blue light makes it out and gets into our eyes. This is why we see we see blue monkey butts!
So now you will never look at a monkey’s butt the same way: you will know what makes it blue! You will even be able to hold your own if this topic ever comes up on a first date…
Wow
Why would they have this evolutionarily?
What purpose does it serve?
An accentuation in the jungle is a target.
Hamadryas Baboon Butt
Many members of the baboon family, like this hamadryas baboon, have prominent buttocks. Unlike many other primate species, the baboons are largely terrestrial, living on the ground in fields and deserts rather than up in the trees. They, like us humans, have the need for some kind of padding on the rear end so they can sit down comfortably for long periods of time. These baboons have what can best be described as calloused, puffy skin on the buttocks; not super attractive, at least to us, but very effective for sitting, which is the baboon’s favorite position.
Celebes Crested Macaque Butt
The Celebes crested macaque, also known as the crested black macaque, is perhaps best known for its fantastic selfie skills. But it’s also an interesting creature, butt-wise. Both the males and females of the species are highly promiscuous, and the female macaque uses its outrageously swollen rear end to indicate that it’s receptive.
Mandrill Butt
And that brings us to the primate with the most colorful buttocks of all: the mandrill. The mandrill is the largest non-ape primate, and also arguably the most colorful, with a trademark bright red and blue nose and a frankly gorgeous rainbow-colored butt. These are secondary sexual characteristics, present in both sexes but much more vibrant in males. Just look at that butt!
To answer these questions, it is important to first understand how light interacts with living stuff, which we call biological tissue. Light is a collection of little packets of energy, called photons, that whiz through the air. Photons come in all different colors, and when these colors are all together, we see white light (like sunlight or light from a light bulb). But photons of different colors act differently when they enter biological tissue.
You can think of a photon as a drunk person walking through a forest. The drunk person enters the forest and walks into a tree, D’oh!, changes direction (scatters) and walks another short distance and into another tree, D’oh! D’oh! D’oh! D’oh! …. and before you know it the drunk person exits the forest in a random place going a random direction.
When photons enter the skin, it is just like the drunk person walking in the forest. Photons bounce off collagen fibers (instead of trees) and emerge from the skin at a random place. In optics, we call this diffuse reflection. A visual representation of diffuse reflection is when a LASER beam hits the surface of milk, giving off a “glow ball” around the LASER spot. (You can also catch my personal demonstration HERE).
Before it gets detected by your eye, a single photon that penetrates a biological tissue (like skin) will randomly scatter within the tissue many times. But it is important to consider that skin is more complex than the forest analogy. Skin is composed of many layers and contains pigments such as melanin, and this affects how photons scatter. This added complexity is the secret to the blue monkey butt.
To understand how photons move through a complex tissue like skin, lets compare a red photon with a blue photon as it hits two tissue layers. Tissue “A” is on top, and Tissue “B” is underneath. If layers A and B were both white (like milk), they would reflect red and blue photons equally and you would see both colors.
But in real skin, the top layer (Tissue A) has only a little melanin, while the next layer of skin (Tissue B) can contain a lot of melanin, which is important because melanin absorbs light, “killing” any photons that encounter it!
In the picture above, both the red and blue photons bounce (scatter) 4 times while they are penetrating the skin. But because the red photons travel a longer distance in between scattering events, they manage to penetrate both layers of skin. The melanin in Tissue B absorbs the red photon so it can’t leave the skin and reach your eye.
In contrast, the blue photons take very short steps in between their scattering events, and they don’t penetrate very deep. They do not make it past Tissue A before they emerge and hit your eye.
A baboon’s butt tissue is arranged somewhat like the illustration above so that blue photons are reflected and all of the other photons (like the red ones) are absorbed. Only the blue light makes it out and gets into our eyes. This is why we see we see blue monkey butts!
So now you will never look at a monkey’s butt the same way: you will know what makes it blue! You will even be able to hold your own if this topic ever comes up on a first date…
Wow
some of y'all need to fukking relax, just because monkeys have been used as a slur doesn't mean calling someone a baboon ass is a Black slur. they not even black 
