Revealing the cause of the cock loss

The results of a new study reveal why some birds, including chickens, have shrunk their penis during evolution.

Birds of chickens, including chickens, peacocks, hemorrhoids, . often develop the penis when they are still embryos, but until adulthood there is only a genitalia in the primitive state. According to research published in Current Biology, these birds have initiated a " gene program" , which plays a role in preventing new penile eruptions.

When growing up, the rooster only has a small shrunken penis.

The loss on the male gave the female more control over the breeding process.

Dr. Martin Cohn, co-author of the study from the University of Florida (USA), said: "We found, the decline of penis growth in the evolution of birds occurs due to activation. of a normal mechanism that destroys cells in a new location such as the developing penis head ".

The team found that a gene called Bmp4 plays a key role in this process. At the stage of chicken development, when Bmp4 is activated, the growing penis of the rooster will begin to shrink.

The red area indicates the penis of the chicken at the embryonic stage before it starts to shrink.(Photo: BBC).

In Australian ducks and ostriches, birds retain the penis, the Bmp4 gene is always "off" and the male genitalia continues to grow.

Due to the absence of the penis, chickens and other birds of the chicken set must develop a reproductive method that is not based on the ability of the "little boy" to penetrate . Both males and females have a vented hole . When "love" , these two acupuncture points will be close to each other, helping to transfer sperm into the reproductive tract of the female. This process is also called "vented kiss".