Lions are a species with obvious dimorphism. The typical characteristic of male lions is a thick and conspicuous mane, which becomes darker with age.

The thick dark mane makes the lion look more domineering. But you know what? In fact, the mane of a male lion is actually a very unfavorable factor in an environment like the African savannah.

It can even be regarded as a shortcoming of the male lion. It is not as defensive as some netizens said and can prevent the throat from being bitten by other animals.

The savannahs in most parts of Africa have a very hot and humid climate, and the black and thick mane on the top is more heat-absorbing and more likely to breed parasites.

Regarding the breeding of bacteria and parasites, people in the early days had a deep understanding. In the 1960s and 1970s, due to the standard of living, people were not as hygienic as they are now, and there were no toiletries as they are today, so many girls will grow parasites such as "lice" on their heads.

And the way to solve this problem is also very simple, that is to shave all the hair.

In addition, although lions hunt and intercept prey most of the time, it does not mean that they do not need to ambush like tigers.

Before chasing their prey, lions will also lurk first, let the prey approach their ambush circle, or actively sneak into the vicinity of the prey.

The thick mane of a male lion will be more conspicuous in an environment such as the African savannah that lacks shelter, and it will be exposed to the prey at once, so it is also a disadvantageous factor for hunting.

Many people may say that lions don't need to hunt! But in fact, the wandering male lions before entering the lion group are completely self-reliant, and even after entering the lion group, they do not always participate in hunting.

According to the theory of "survival of the fittest " in "Evolution", since the mane is an unfavorable factor for lions, why not eliminate this trait in the long process of species evolution?

Obviously, there are deeper reasons why the lion is willing to bear this shortcoming. In other words, the benefits of thick and dark manes far outweigh these disadvantages, so they did not eliminate this trait during the evolution process.

So what is the reason? Scientists believe that it may be related to "sexual selection".

Sexual selection is a special form of natural selection. The famous biologist Darwin believed that individuals of one sex in the two sexes compete with other individuals of the same sex in the population for mating, and the mated individuals can reproduce offspring.

The traits that are conducive to competition are gradually consolidated and developed.

To put it simply, when a certain characteristic of a male is very popular with females, then the male can obtain the right to mate, thereby procreating offspring and inheriting the trait. So that this favorable feature is inherited and consolidated in future generations.

The black and thick mane of the male lion is the favorite feature of the female lion. In the eyes of female lions, a male lion with a black and thick mane is a symbol of handsome， healthy, and better genes.

Because despite many unfavorable factors, the male lion can still maintain good health, which shows that its physical fitness is stronger and its ability to resist parasites is stronger.

At the same time, the concentration of testosterone is higher, which is naturally a symbol of excellent genes. Then the offspring produced by mating with it will have a higher probability of being better.

Therefore, according to the theory of "sexual selection", male lions not only did not abandon their thick manes during the evolution process but instead competed to develop darker and thicker features to attract the favor of female lions.