Giraffes are currently the tallest animals on land, and a male adult giraffe is between 4.8 and 5.5 meters tall, almost as tall as two stories, and weighs 900 kilograms.
The tall body and powerful limbs did not keep the giraffe away from the attack of the beasts, in fact, in Africa the giraffe would be besieged by lions or hyenas, and the young giraffes would be injured by leopards. Therefore, the life of giraffes is not stable, and they have to face dangers from their surroundings at all times. So sleeping became an old problem for giraffes.
Giraffes have the same number of cervical vertebrae as humans as 7 cervical vertebrae, which means that they can be very difficult to do any neck-related movements. Coupled with their slender limbs, they could not lie on the ground and rest peacefully like their close relatives deer or cattle. Because, if the enemy sneaks in while resting, the giraffe cannot quickly stand up straight, and even if it can stand up, it will appear dizzy due to the temporary lack of blood supply to the brain, and it will be hunted and killed because it cannot respond effectively to the attack of the beast.
So giraffes evolved their sleep time to be very short, compared with the 20 hours of sleep per day in lions, the giraffe sleep time is only 2 hours at most. Moreover, in order to prevent attacks during sleep, they also allocate this only 2 hours of sleep to the whole day. Each break is only a few minutes, which is equivalent to a human nap. Therefore, giraffes not only sleep for a short time, but also have a hard time enjoying a deep sleep. According to zoologists, sometimes giraffes sleep only about 20 minutes a day, so much so that before the 1950s it was thought that giraffes were sleepless.
Although giraffes just stand and squint for a while most of the time, so much so that the surrounding animals and humans don't realize that the giraffes have rested. But in an environment where there is no danger, they will still enjoy it comfortably and have a deep sleep.
The picture above is the state of deep sleep of giraffes, it is difficult for them to have such a comfortable life in nature, if a giraffe does this in nature, it may be waiting for it is the crazy siege of lions.