We've all seen pictures of camels carrying heavy loads (负载物) across the sandy desert. They walk without stopping for food or water for several days.
Have you ever wondered how they do it? For your answer, take a look at the bag round hump which is on a camel's back.
Camels are the only animals with humps. And it's the hump that gives camels the amazing ability to go for long periods of time without food or water. The hump is like a spare cupboard (备用食物柜) where the camel stores (储存) food and water for days when there is nothing to eat or drink.
When life is good, and there is plenty to eat and drink, a camel's hump can grow to as big as 40 kilograms. The food is changed into fat (脂防) and stored in the camel's bump.
When there is nothing to eat or drink, camels begin to use the stored fat in their humps. That's why they can continue to live for weeks without food and up to 10 days without water.
Camels are like sponges. They can take in more than 130 litres of water in one short drink. In only a few minutes, all of this water goes directly to the camel's blood cells (组胞).
Camels save water too. They never know when they'll find the next watering hole. As they breathe out, their noses close quickly. The water in the breath stays in their bodies.
After a long trek across the desert carrying 100 kilograms or more, a camel can lose up to 150 kilograms of weight. The camel's hump will become very small. As soon as this camel gets to an oasis (绿洲), it will take in hundreds of litres of water. In a day, it will get back most of its weight.
Nature really has given camels the perfect system for living the hard desert life.
