During the National Day holiday, visiting the zoo is a travel choice for many people. When it comes to the most popular animals in the zoo, in addition to the national treasure giant panda, the tiger, the "King of Beasts", is definitely on the list. If you have some knowledge about tigers, or have read the instructions on the zoo's display boards, you will find that the description of tigers is as follows:"The color of a tiger's fur and the patterns on it are a kind of camouflage that can better hide itself."
Image source: SOOGIF
Here’s the problem: The tiger’s fur is yellow-brown and its stripes are black. It can be said to be very conspicuous lying in the green grass. Herbivores like wild boars and sika deer turn around and run away without even seeing them at a glance? What about pretending? Could it be that what is said on the display board and in the encyclopedia is wrong?
In fact, this is not the case. Today we will talk about why yellow-brown and black-striped tigers can hide themselves in green forests. Read it carefully and you can show it off when you visit the zoo!
Why is the tiger's fur brown?
There are indeed many green animals, such as frogs, lizards, and birds. Many of them are green. Only mammals are almost all yellow, brown, brown, black, etc. Although many species have particularly complex and beautiful spots or patterns on their bodies, none of them are green! Why is this? Don't animals like green?
Lizard, photo credit: SOOGIF
It turns out that the coat color of various animals is expressed by the pigments present in the animal's fur or medullary cells. In mammals, there are only two pigments, eumelanin and pheomelanin. Eumelanin can make mammalian hair black and brown, while pheomelanin can make hair red and yellow.
In addition, under the influence of the albino gene, the fur will appear white, and the combination of these colors makes the main color of the fur of most mammals black, brown or white, which determines the tone of the fur color of mammals. Although they also come in bright red, bright yellow, gray and other colors, and many species have dazzling spots and stripes, they rarely have beautiful blue, green and other colors.
Some well-informed friends will refute: "Why are some sloths green?" This is because there is some algae attached to the sloth's fur. When the algae grows very lush, it naturally looks green.
Sloth blending into the environment, photo credit: piqsels
So, why aren’t tigers green? It’s not that it intentionally struggles with life, it’s because it simply can’t produce the pigment that makes its fur appear green!
These animals turn out to be "color blind"
Of course, even if the tiger is not green, it can still hide itself in the grass.
The main food of tigers is various large herbivores, such as wild boars, deer, cattle, sheep, etc. These animals are precisely "color blind". There are only two kinds of cones in their eyes, one is red and the other is blue. They lack the cones that sense green, so they cannot distinguish between red, orange, yellow and green. Anyway, your prey can't see green, so turning yourself green is unnecessary.
Little lamb, photo source: SOOGIF
In fact, primates represented by us humans are considered "alien" among mammals. There is a hypothesis: In the Mesozoic Era, our mammalian ancestors lived in an era when dinosaurs flourished. In order to survive, they basically slept in caves during the day and ran out to find food at night while the dinosaurs were sleeping. The light at night was poor and it was difficult to distinguish colors. Therefore, the ancestors of primates focused on developing sensory abilities such as smell, touch, and hearing, and vision also developed in the direction of focusing on distinguishing objects.
However, this branch of primates is highly adapted to arboreal life and feeds on various plants. The flowers and fruits of plants are "high-end foods" with high nutritional value, especially the fruits, which are more delicious. However, the taste of the fruits is very different before and after maturity. Many fruits are sour and astringent when immature, making it difficult to swallow. The color of the fruits often changes after maturity, such as apples, oranges, etc. The purpose of their colorful colors is to remind animals that feed on fruits to come to feed, and ultimately help plants spread their seeds.
In the process of evolution, primates have three types of cone cells and have mastered the ability to perceive changes in the environment and surrounding objects through color. Herbivores such as deer, cattle, sheep, and horses hardly use color to distinguish food, so the world in our eyes is much more colorful than these herbivores.
You see, this is not a mistake between the encyclopedia and the display board. Although the tiger is a "conspicuous bag", the eyes of its prey are not good.
The "camouflage color" of animal fur
Of course, as an apex predator, tigers don’t have to worry about animals being able to prey on them as long as they are not discovered by their prey. However, many animals hide themselves to protect themselves, such as the kakapo in New Zealand. The feathers of many parrots are extremely bright, but the body color of the kakapo is It seems a bit "plain". There is a view that the kakapo has adapted to life on the ground and cannot fly, and its natural enemies are some large raptors. When encountering danger, the plain feathers and grass can blend together. As long as the kakapo does not move, enemies in the sky cannot detect it.
Transparent fry, picture source: wikipedia
The crucian carp and carp we usually eat have darker colors on their heads and backs, and lighter colors on their abdomens. They are also a kind of camouflage color. When looking down from the water, they can blend in with the water surface, but when looking up from the water, they are also not so conspicuous. Of course, the lack of color may also be a good camouflage, such as the willow leaf-shaped larvae of Japanese eel and whitebait. Their bodies are almost transparent, and it is difficult to find a fish there as long as they are still.
Ye Wei, picture source: wikipedia
When it comes to using body color for camouflage, some insects are geniuses, like the praying mantis. Some mantises have body colors that blend in with the moss on tree bark, while other species are as bright as a flower and difficult to spot among the flowers.
The leaves (xiū) and some stick insects are even more exaggerated. In addition to the camouflage of body color, they also have the camouflage of body shape and posture. One turned himself into a leaf, the other turned himself into a branch, and even had some traces of imitating being chewed on the corners. It can be mistaken for the real thing. It is the first among molluscs. Pedopods have mastered stronger magic. They can change their body color by retracting and retracting the pigment cells of their skin, truly integrating themselves with the surrounding environment, and they can also change at any time. Some octopuses can even use color change and change the shape of their tentacles to disguise themselves as other marine creatures.
After learning so much, why not go to the zoo to show off during the holidays?