Residual organ
A residual organ is a rudiment that remains in the animal’s body and does not perform any functions. Due to mutations, it remains in the body of the individual throughout its life. The absence of an organ is the result of genetic changes, so the phenomenon is an anomaly. From the moment of their appearance, such rudiments only interfered with the evolutionary process; only after millions of years was the body able to get rid of them completely. At present, the animal has already formed a small number of residual organs, but the duration of their existence is short. Often, not one organ fails, but several at the same time. This often entails the death of the body ahead of schedule. Rudiments appeared in the process of evolution and are the result of adaptation to new environmental conditions. Their original purpose is becoming a thing of the past, as a result of which they are forced to get rid of excess load.