What is the hen calling?

It is a natural law that hens lay eggs and cocks crow. This is like the territory where lions hunt and patrol. But in reality, hens will crow, which is a rare phenomenon and is called "hen morning". In rural areas, because many people can raise chickens, the probability of hens in the morning is higher. But the hen's crow has always been regarded as an "ominous sign". So, why does the hen bark when it's okay? Let's talk about this problem from a scientific point of view.

The crow of hens was recorded for the first time in the ancient book Shangshu Pastoral Pledge. Original text: "Chickens have a way to seize the day." It means that when a hen crows, the family is ruined. Later, it was extended to "the woman is in power, and the country is ruined." Because of this statement, in many rural areas, hens are killed as soon as they crow.

Why is crowing a rooster's "unique skill"?

Have you ever thought about a question: It's also a chicken, why does the cock crow, but the hen can only "giggle"? Let's start with the vocal organs of birds. Birds all make sounds, because they all have an organ-the sound tube, which is equivalent to the vocal cords of mammals. The structure of vocal tract is not complicated, and it is mainly composed of muscle group (vocal muscle), cartilage (vocal bone), vocal membrane and semilunar membrane. When the airflow enters the vocal tract through the trachea, the vocal cord membrane and the meniscus membrane in the vocal tract vibrate to produce a cry.

But the sounds made by different birds are different, some are monotonous, hoarse, harsh and some are euphemistic, which are mainly determined by three factors: the developed degree of vocal cord muscles, the thickness of vocal cord membrane and the moving speed of vocal cord bones.

The movement speed of vocal cord bone is controlled by vocal cord muscles, so these two factors can be combined into one. Dr. Cohen-Ilmans of the University of Southern Denmark found that the more developed vocal cord muscles are, the faster vocal cord bones move when singing, which leads to more euphemistic calls. In addition, vocal cord muscles can also control the pitch and volume of songs, and the thickness of vocal cord membrane mainly determines the sound level, that is, controls the timbre. Knowing the sound of birds, let's see why hens and cocks make such different calls.

The problem lies in the thickness of vocal cord membrane and the developed degree of vocal cord muscles. According to the anatomy of the vocal cord duct of chicken, the vocal cord membrane of rooster is thinner than that of hen, so that when air flows through the vocal cord duct, the obviously thinner vocal cord membrane makes a sharper sound. Secondly, the development of vocal cord muscles determines the movement speed of vocal cord bones. Although the vocal muscles of roosters and hens are relatively small, they are relatively more developed. So the rooster will crow, and the hen will only giggle like the rooster. Secondly, roosters crow as a means to summon companions and attract the opposite sex in nature, so roosters crow almost every day, while hens rarely need to communicate, so they only crow after laying eggs or when they are frightened.