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Why There Are No Green Mammals!

It would seem as though there have been a number of questions added to various quizzes recently about green mammals due to seeing a huge spike in the number of people reaching out and asking a number of questions about green mammals recently.

Due to this, we have decided to publish this article going over the main questions that we see people asking time and time again in the hope that we are able to help our readers understand why there are no green mammals.

Although some people do class the three-toed sloth and a few other sloth species as a green mammal, the green look on their fur is actually due to the growth of a green algae called Trichophilus welckeri that naturally grows on their fur.

This is a symbiotic relationship between the sloth and the algae as the coat of the sloth offers the ideal place for the algae to grow while the green color of the algae helps to hide the sloth in the tree tops.

Due to the green look of these mammals being due to the algae growing on their coat rather than the actual pigment the mammal develops, it is not actually a green mammal.

That said though, some of the quiz questions relating to green mammals will class the three-toed sloth as the only green mammal on the planet even though it technically has a brown coat.

Are There Any Green Mammals?

There are no green mammals on the planet due to mammals lacking the required pigment to develop green in their skin or fur.

Some people do class the three-toed sloth as a green mammal but its green look is actually due to the green algae called Trichophilus welckeri living on its coat rather than the sloth producing the green pigment itself.

The green monkey (Chlorocebus sabaeus) is also sometimes classed as a green mammal due to its coat sometimes having a green tint to it but the coat of the monkey does not actually have any green pigment in it.

The green tint in the monkey’s coat is due to an optical illusion of the golden outer coat and the grey undercoat that has a slight hint of blue in it.

With the golden outer coat having a high amount of yellow in it and the grey undercoat having a small amount of blue in it, the simple formula of yellow + blue = green comes into play in some lighting conditions giving the monkey the appearance of having a slightly green coat.

Again though, just like the three-toed sloth, this is not due to the monkey actually producing a green pigment itself so it is technically not a green mammal.

A green sloth high in a tree.

Can Mammals Develop Green Pigments?

Although some mammals can develop green pigments, this is usually only restricted to their eyes and even then, it is due to a mutation.

Mammals are not able to produce a green pigment for their fur due to the core makeup of mammal fur being one of two types, a black/brown pigment and a yellow/red pigment making all mammals develop a range of those colours for their coat.

It is believed that the lack of ability to produce a green pigment for fur in mammals is due to evolution and the face that the fur of a green mammal would look bright green under the green light filtered by tree leaves.

This would cause any green mammals to stick out like a sore thumb in their natural habitat and be easy prey for their natural predators.

The two core combinations of mammal fur of black/brown and yellow/red look like a deep grey/brown/black under the green filtered light of the treetops offering them much better protection from predators.

This is why it is believed that if there ever were any green mammals, they were filtered out of the gene pool via natural selection many thousands of years ago and there is no trace of their DNA left in mammals today.

Which Mammal Is Green In Colour?

There are no mammals that are naturally green in color.

The three-toed sloth and other sloths appear to be green due to the green algae called Trichophilus welckeri growing on their skin and green monkeys (Chlorocebus sabaeus) appear green due to an optical illusion of the two primary colors of their coat and even then, it is only in specific lighting conditions.

There is a very rare situation where polar bears can develop a green look to their coat but this has never been seen in their natural habitat and is believed to only occur in polar bears in captivity in warm areas.

The green that develops in their coat is also due to an algae similar to how the three-toed sloth gets its green look and a quick bath with salt will remove the algae from the polar bear and return its coat to being its natural white color.

We have seen a number of people thinking that whales are able to have a green skin but this is not correct either.

This is due to a similar situation of the polar bear and three-toed sloth with a green looking whale being covered in the Diatom algae.

As the whale migrates to colder waters, the algae will die and fall off the whale returning it to their natural, non-green color.

Are There Colorful Mammals?

Other than the mandrill and baboon there are no particularly colorful mammals. Although baby langurs can be particularly colorful, they do tend to lose the brighter colors as they grow and develop their adult fur coats.

This is due to most mammals lacking the ability to naturally grow colorful furs and even the mandrill and baboon have their bright colors on their skin, not their fur.

Other than those three unique mammals, there really are not any other colorful mammals due to the pigment restrictions that mammals have evolved with.

Being able to produce a very small number of colors naturally really do restrict the colors of mammals compared to some other types of animals.

As we touched on earlier though, this is believed to be due to natural selection with the brighter color mammals being easier to see in their natural habitats and early predators being able to pick them off and filter their DNS out of the gene pool.

Fast forward to today and add many thousands of years of breeding to the various types of mammals and any genes that did allow for the creation of brightly colored mammals has been filtered out.

Mammals Green Camouflage!

A number of mammals have developed symbiotic relationships with various types of algae over the years to offer them a green tint to their coat to help them hide in the treetops with ease.

The mammals coat offers the ideal living conditions for the algae to thrive in while the green tint offered to the mammals coat allows it to hide from predators easier.

Unlike the naturally green pigments developed by some other types of animals, the green tint added to the coat of some mammals such as sloths due to this relationship is a very slight hint of green.

This prevents their coat from turning bright green in the green filtered lighted by tree leaves and helps to prevent them from sticking out.

The algae that grows on whales seems to offer minimal benefit though and is more parasitic than symbiotic in most cases.

That said though, the algae that does grow on whales does not seem to hurt them and as we touched on earlier in the article, most of the time, the algae will simply die and fall off as the whales migrate to colder waters.


That brings our article going over green mammals to an end. We hope that we have been able to help our readers understand why there are no green mammals as well as why mammals are not able to naturally develop green pigments. If you did find this article due to a quiz asking about green mammals then the answer is probably the three-toed sloth with the green monkey sometimes being classed as correct too even though neither of them are actually green due to their pigments.