Attack, defense, and speed are all bad. How did the koala survive?

Koalas, also known as koala bears, are cute mammals. It is surprising that they can live in the same era as us.

In the history of the earth, there have been tens of millions of animal species, but most of them have been eliminated by nature on the road of evolution. Those that have survived to this day are dominant species that have overcome all obstacles on the road of evolution. Some animals have strong attack capabilities, which makes them the best in the cruel competition for survival; some animals have average attack capabilities, but good defense capabilities, which also makes them invincible; and some animals, although their attack and defense capabilities are poor, have super speed, so they can still occupy a place in nature. On the other hand, koalas have no advantage in attack, defense, or speed.

Koalas live their entire lives on eucalyptus trees. Apart from eating and reproducing, they spend the rest of their time sleeping. Yet, this creature has not yet become extinct.

It seems a bit unreasonable that just sleeping can surpass natural selection. In fact, it is not sleeping that gives koalas a survival advantage, but the place where they sleep. Judging from the behavior of koalas, if koalas have natural enemies, it will not take long for them to be eaten to extinction, but koalas have no natural enemies. Why does a slow-moving herbivore have no natural enemies? Because there are no predators living in the same area as koalas. Eucalyptus forests are a piece of pure land that predators are unwilling to go to. In nature, carnivores often face more brutal competition for survival than herbivores, so "not being picky" is an important guarantee for the survival of carnivores.

If a carnivore develops the habit of feeding only on a certain type of herbivore, it is difficult to ensure the continuation of the species. The eucalyptus forest is such a monotonous ecosystem. Here, apart from koalas, there are almost no other small herbivores. Therefore, this place is a "food desert" for carnivores, and no diners are willing to settle here.

So why are there almost no other small herbivores in the eucalyptus forest? Because most herbivores cannot eat eucalyptus leaves, which are the exclusive food of koalas. Other animals do not eat eucalyptus leaves not because eucalyptus leaves are unpalatable, but because eucalyptus leaves contain a cyanogenic glycoside compound, which is a toxin for other animals.

Why are koalas not afraid of poison? Because koalas have the ability to decompose cyanogenic compounds, and the microorganisms in their intestines can also assist in decomposing cyanogenic compounds.

Since young koalas have a poor ability to decompose cyanogenic compounds, mother koalas will feed their cecal excrement to their children. The microorganisms in these excrement can help young koalas decompose the cyanogenic compounds they have eaten. So are koalas the only ones with this ability? Of course not. Other herbivores do not eat eucalyptus leaves, not only because the leaves contain toxins, but also because the nutritional content of eucalyptus leaves is low and it is difficult to maintain daily consumption. However, koalas do not have such troubles, because their energy consumption is very low, whether it is their brain or their body.

Not only do koalas look cute, they are actually not very smart. The brain is a high-energy consuming organ, and having an underdeveloped brain can effectively reduce the body's energy consumption. In addition, koalas spend most of the day sleeping, so their overall energy consumption is even lower. So even though eucalyptus leaves have limited nutrition, it is completely enough.

The world is so big that there are many wonders. Koalas have gained a unique survival advantage in the cruel natural competition with their two disadvantages of being "stupid" and "lazy". Life is really a very wonderful thing. Although koalas live in their own eucalyptus paradise, they are not all worry-free today. They have been listed in the "Red List of Endangered Species of the World Conservation Union" and are classified as "vulnerable". Why are koalas a vulnerable species? There are two reasons.

Although koalas have no natural enemies, they are exposed to forest fires and climate change. Another key factor that makes koalas vulnerable is human activities.

Before the British landed in Australia in 1788, the number of koalas in Australia was calculated in the tens of millions. After that, humans began to attack koalas. According to records, more than 2 million koala skins were exported in 1924 alone. Although the local government began to legislate to protect koalas, the number of wild koalas today is still less than 100,000, which is pitifully small compared to the tens of millions at its peak. Although humans are part of the life on Earth, the impact of human activities on the Earth is far beyond that of other animals, so humans must try to reduce the impact of their own activities on the Earth's environment and other organisms. Protecting the Earth's environment and protecting biodiversity is protecting ourselves.

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