If a tail grows in humans, it is called a human tail or vestigial tail. Many experts believe that human ancestors had a vestigial tail and, at some point, needed it. However, as humans evolved as species, the requirement for such an organ ended, which is why Humans no longer grow them.
This blog comprehensively understands the human (vestigial) tail, its causes, and treatment.
What is the vestigial tail?
Most humans grow a tail in the fetal stage in the womb. The embryonic tail disappears by eight weeks and usually becomes the coccyx or the tailbone. The tailbone or the coccyx is located at the end of the spine, beneath the sacrum. However, sometimes the embryonic tail does not disappear, resulting in an individual born with it. It is a rare occurrence.
While growing a true human tail is very rare, sometimes, when babies are born, parents may think their baby has a true tail when they don’t have it actually. This is known as pseudo tail. Generally, pseudo tails are a symptom of spina bifida or of an irregular coccyx as against to a remnant of the embryonic tail from the womb.
Human tails have the following features:
- They have muscles, blood vessels, nerves and connective tissue
- They are covered with skin always and is located on the tailbone
- They can grow as long as 13 centimetres
- Sometimes, they can even contract or move
Human tails does not have bone, cartilage, or spinal cord.
When should you call the doctor?
The doctor can help eliminate the structure to improve the quality of your life.
What are the causes of a vestigial tail?
While tails are extremely rare in human beings, temporary tail-like structures are present in the human embryo. These tails develop during the fifth or sixth week of gestation. A tail is not found in most people at birth since the structure disappears or absorbs into the body during fetal development, constituting the coccyx or tailbone.
The tail disappears in the embryo during the eighth week of gestation. However, in rare cases, the tail sometimes remains because of a defect during the developmental stage (Germinal Stage, Embryonic Stage, and Fetal Stage). In cases of a ‘true’ vestigial tail, this defect’s exact cause is unknown.
Some people are also born with a pseudo tail, which is not the same as a ‘true’ vestigial tail. A pseudo tail can look similar to a vestigial tail, but it is generally due to an elongated coccyx or spina bifida (a neural tube defect).
How is a vestigial tail treated?
The decision on whether to seek treatment for a vestigial tail depends on the severity of the condition. Some tails are tiny and do not result in any problems. However, longer tails can interfere with sitting in the long run. These tails may extend up to 5 inches.
The vestigial tails usually do not cause pain or discomfort because they don’t contain any bone. There can be pain with a pseudo tail since they include bone or vertebrae. Babies born with a vestigial tail must undergo an imaging test such as an MRI or an ultrasound to classify the tail and ensure it is not related to a medical condition such as spina bifida.
A vestigial tail is treated with surgery since a ‘true’ vestigial tail is composed of adipose and muscular tissue. The doctors can quickly eliminate these types of tails with simple excision. The procedure does not lead to any residual side effects.
Parents must remember that tail removal is not medically necessary, although some parents opt for surgery for cosmetic reasons. The parents can also decide to remove the structure from their child soon after birth, whereas some people born with tails continue to live with it for several years. In some instances, it is not entirely apparent if the tail is a true tail or not.
People who have a vestigial tail can have it removed through a simple procedure or choose to keep the tail if it is small. Living with a vestigial tail does not lead to complications or result in any long-term problems. However, if people remove the tail, the outlook is good, and eliminating the structure does not cause any adverse effects. The decision to remove or keep it primarily depends on the impact the tail has on lives. If it upsets people or prevents them from having intimate relationships, then surgical removal of the structure can improve the quality of their life and boost their self-confidence.
Frequently Asked Questions (FAQs)
What are the most common characteristics of a vestigial tail?
Some of the most common characteristics of a vestigial tail are:
- They are composed of muscles, connective tissue, blood vessels, and nerves
- They are situated on the tailbone and always covered with skin
- They can extend up to 13 centimetres
- They can sometimes even move or contract
Human tails are not composed of bone, cartilage, or the spinal cord.