People with tails really exist

In some sci-fi series or cartoons there are human beings who have a tail. What a fantasy you might think, but did you know that 23 cases of human vestigal tails have been reported since 1884? This means that one baby is born with a tail every 5½ years. Sometimes this is just an appendage, but it also happens that a real tail has been developed. Many scientists claim this is evidence for the theory of evolution, others claim it’s just a mistake by Mother Nature. Table of contents:

  • Difference between true tails and pseudo tails
  • Evidence of evolution & origin of a rudimentary tail in humans
  • The longest human tail

 

Difference between true tails and pseudo tails

The true (also called persistent ) vestigial tail of humans arises from the most remnant of the embryonic tail and is formed in the region of the coccyx. This tail contains fatty and connective tissue, central bundles of striated muscles, blood vessels, nerves and is covered by skin with hair (fouls) and sweat glands (as in animals). What is missing from the tail is bone, cartilage and the (continuous) spinal cord. However, there are also a few cases where newborns with a real tail had as many as five developed vertebrae. The persistent tail can move in some cases (the person has control over it) and is twice as common in males than in females. The genetic component of this condition is very small and so in most cases the condition is not hereditary.
Pseudo-tails are abnormalities/deformities (these may vary) that look like a protuberance and superficially resemble a real tail. These do not arise from the preservation of fetal structures and, unlike real tails, cannot move. About a third of reported human tails are pseudotails. The most common cause of these pseudo-tails is an abnormal elongation of the coccygeal vertebrae (tailbone). Abnormalities in these tails often include two lipomas (benign fatty tissue growths), a glioma (growth that arises from glial cells [cells of the nervous system, in this case from the spinal cord]) and an elongated, thin parasitic fetus. Pseudotails are usually caused by a mutation and are not hereditary.
Another way in which a tail can develop in humans is through the condition spina bifida . This is a birth defect in which the spine does not close properly during development. This is usually caused by too little folic acid during conception and the early stages of pregnancy. As a result, spinal fluid squirts out and forms a kind of flesh-like sac. This type of tail is common and can be recognized by the location of the tail: the tail is placed higher on the back or even under the neck, while a true tail is really an extension of the tailbone at the end of the spine.
The tail itself is not actually a vestigial organ, but an atavism . This is a characteristic of an ancestor that appears sporadically. The rudimentary part is actually the coccyx (tailbone). Yet the tail is often still referred to as a relic.

Evidence of evolution & origin of a rudimentary tail in humans

Normally in humans, the tail is present in the developing human fetus. This embryonic tail is approximately one-sixth of the total length of the embryo and is most prominent when the embryo is 31-35 days old. This tail is normally absorbed by the rest of the body in the eighth week of pregnancy. In babies born with a tail, something went wrong: the structures of fetal development are preserved instead of broken down. The cause of this is a lack of cell destruction ( apoptosis ) of the embryonic tail. The tail can reach an average length of about 2.5 centimeters to more than 12 centimeters.
The real vestigial human tails are seen by many scientists as an example of evidence of macroevolution. A characteristic of evolutionary phenomena is that the phenomena have a biological (i.e. genetic) component. This is the case: there is a known case where three generations of women inherited a real rudimentary tail (however, this is very rare). In addition, it has been discovered that the same genes that cause a tail in rats are also present in humans. These are the genes Wnt-3a and Cdx1. If these genes are not inhibited in the early stages of human development, a tail will most likely develop in humans.
Originally, the tail is functional for mobility and maintaining balance. Nowadays, the tailbone still has a secondary function, namely being an attachment point for muscles. Evolutionary biologists suggest that the tail was lost throughout the evolution of monkeys due to a lack of expression of the Wnt-3a gene. Exactly how this came about is still up for debate. One theory about this is that the loss of the tail is because the tail was no longer needed in the environment in which the monkeys lived. Another theory suggests that it may be due to a (dominant) mutation whose frequency was increasing in the monkey population.

The longest human tail

The longest tail ever measured in humans is 33 centimeters long and covered with hair. This longest tail belongs to a man from India who works on a tea plantation, named Chande Oram. He is very well known locally and is seen as a reincarnation of Hanuman, the monkey god. People who know him claim to have been cured of their illnesses by touching his tail. Despite his local celebrity, he is still single and still looking for a wife. About twenty women have already rejected his proposals because they cannot accept his tail. A human tail can be removed through surgery. This operation can be performed without difficulty and has no consequences for the individual. However, he refuses to surgically remove the tail because he sees it as part of himself.

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