In fact, sleeping standing up is an instinct of birds, which is related to the muscle structure of birds. For example, when humans do "scratching", it is an active behavior that needs to consume energy, while birds "grasping" is passive, and this action does not require too much force. When the bird stays on a branch and grabs the branch with its claws, the weight of the body is concentrated on the tendons. At this time, the tendons will be tightened, the feet will grasp, and the claws will naturally grasp the branches. At this time, the muscles of birds are generally in a relaxed state. So it doesn't take much effort, and birds can enjoy this pose.
In order to adapt to the environment, birds have also developed very strong skills. The cerebellum of birds is very developed and can regulate vision and movement so that it remains balanced and does not fall off when sleeping. However, when the birds wake up and fly, it is difficult. The weight of their whole body no longer presses against their tendons. At this point, the muscles associated with the claws should remain tense. Only then can the birds fly away from the branches.
In order to adapt to different living habits, the toes of birds vary widely. There are forked slender toes that can walk quickly on floating plants; the full webbed toes of geese and ducks are for the convenience of paddling, and the toes are also suitable for swimming in the water; and birds such as pigeons and pheasants have strong legs and feet. They can dig up food on land because their legs and feet facilitate running on land.
In addition, the toes of birds are arranged very differently, and the most common toe arrangement of passeriformes is: second, third, fourth toe forward, and first toe backward. Those ordinary kingfishers, the second, the third, and the fourth toes are all forward, but the paws are almost ready. In addition, there are pairs of toes, and front toes, and isotoes.
According to studies, the pectoral muscles associated with flight in birds are particularly developed, and these muscles account for about one-fifth of the weight of the body weight. Its pectoral muscles can emit great force and can pull wings. But the back muscles of birds have degenerated, as opposed to fish.
The pectoral muscles of birds are generally divided into pectoralis major muscles and pectoral minor muscles. The former begins with the keel process and reaches the ventral position of the humerus, where the wings can be lowered when contracted; the latter begins with the keel process and uses the long tendons to pass through the collarbone and the three bone holes formed by the shoulder blade. Terminates at the posterior part of the proximal humerus and can be lifted when contracted.
The muscles of the bird's hind toes are concentrated on the thighs, connected to the toes with long tendons. In this way, the muscles that govern the front and rear toes are concentrated in the middle of the body, which is important for birds to maintain physical stability when flying. Because birds often fly to practice their stability, this is one of the reasons why birds sleep on branches and do not fall.
Friends, do you understand?