Why can giant pandas grow so fat even though they only eat bamboo?

Giant pandas are our national treasure and one of the cutest animals in the world. Their cute appearance and love of eating bamboo are so popular that people can't help but want to hug them. But have you ever wondered why giant pandas can grow so fat by eating only bamboo? Bamboo is a low-calorie, high-fiber food. How can it satisfy the energy needs of carnivores like giant pandas? This article will reveal the bamboo mystery of giant pandas and let you know more about these cute national treasures.

1. Why do giant pandas choose bamboo as their main food?

Giant pandas evolved from ancient bears and were originally carnivores. However, about 11 million years ago, due to climate changes caused by glaciers, giant pandas only survived in Sichuan, Gansu and other regions, and their numbers were relatively small. At that time, it was difficult for them to find live prey around. The hungry giant pandas struggled painfully and had no choice but to eat bamboo, which was relatively lush at the time.

There are two main reasons why giant pandas choose bamboo as their main food. First, bamboo is a readily available food, while other foods face fierce competition. Second, bamboo shoots and leaves can provide protein close to meat, and the giant panda's digestive tract, enzymes and microorganisms can also handle high-protein diets.

2. How do giant pandas get enough energy from bamboo?

Although giant pandas have adapted to eating bamboo, they cannot get enough energy from bamboo. Bamboo contains a lot of cellulose and hemicellulose, which are difficult for most animals to digest. Although giant pandas have some microorganisms that can decompose cellulose and hemicellulose, they are not efficient. Therefore, giant pandas mainly get energy from starch, pectin, etc. in bamboo.

Starch and pectin are polysaccharides that can be broken down into single glucose molecules by enzymes in the giant panda's body, which are then absorbed into the blood to provide energy. Compared with other woody plants, bamboo contains relatively high concentrations of starch and pectin. Moreover, the starch and pectin content of different parts of bamboo changes with the seasons, and giant pandas always choose to eat parts of bamboo with high starch and pectin content.

3. How do giant pandas maintain their weight balance?

Even though giant pandas get some energy from bamboo, it is still far from enough for them. Giant pandas eat about 12-38 kilograms of bamboo every day, which accounts for 15-40% of their body weight. However, they can only digest about 17% of the energy in bamboo, which is equivalent to only consuming about 9,000 kcal of calories per day. This is far from enough for an adult giant panda. So, how do giant pandas maintain their weight balance?

One of the pandas' key strategies is to save energy. They have a small range of activity, walking only a few kilometers a day. They also move slowly and don't make many violent movements. Their body temperature is also lower than other animals, at around 37 degrees Celsius. They also have a thick coat of fur that helps retain body heat and reduce energy loss.

In addition to saving energy, another important adaptive feature of giant pandas is their fat metabolism. Fat is a high-energy substance that can store excess energy and release it when needed. Giant pandas have a special lipase that can convert the starch and pectin in bamboo into fat and store it in the body. When giant pandas encounter food shortages or cold weather, they can use this fat to replenish energy and keep warm.

4. Why are giant pandas so fat?

Through the above introduction, we know how giant pandas get energy from bamboo and maintain their weight balance. However, this has not answered our original question: Why can giant pandas grow so fat even if they only eat bamboo? Do they really get fat because they eat too much?

In fact, giant pandas are not really fat. They look chubby mainly because they have a thick layer of fur and subcutaneous fat. These fur and subcutaneous fat are not an unnecessary burden, but an important protective mechanism. The fur can protect giant pandas from environmental factors such as cold, humidity, and ultraviolet rays; subcutaneous fat can store energy and provide support when food is scarce or the temperature is too low.

So, giant pandas look fat not because they eat too much or exercise too little, but because they have a complete set of adaptive mechanisms that allow them to survive in harsh environments.