Vestigial organs are those that have lost all or most of their original function through evolution. In humans, some examples of vestigial organs include the appendix, wisdom teeth, the tailbone (coccyx), the muscles of the ear, body hair, and the semilunar fold in the corner of the eye. While these structures may appear functionless, some of them may retain lesser functions or develop minor new ones. For example, the appendix is considered vestigial in terms of its original function, but modern researchers believe it has evolved to play a role in supporting the immune system[1][4]. The concept of vestigial organs is important in understanding evolution and adaptation, as it provides evidence of how organisms have changed over time.
Human embryos do develop a tail during early stages of development, but this tail is usually reabsorbed and disappears by around the eighth week of gestation. The embryonic tail, which typically consists of about 10 vertebrae, is a vestigial structure that is thought to be a remnant of our evolutionary past. In rare cases, a vestige of the tail may persist at birth, resulting in a condition known as a “true human tail.” However, true human tails are exceedingly rare and are usually harmless, often being easily removed. They are not considered functional and are believed to be linked to our evolutionary history. The tailbone, or coccyx, is what remains of the embryonic tail in most humans[6][9][10].
Most humans grow a tail in the womb, which normally disappears by the eighth week of development, growing into the coccyx or tailbone. However, in rare cases, the embryonic tail does not disappear, and the baby is born with a true human tail. This is an atavistic trait, meaning it is a remnant of ancestral features. The presence of human tails, which may be inconvenient or uncomfortable to have, is attributed to genetic and developmental processes, and it is a subject of scientific interest in understanding our evolutionary history.
“Across the developing world, there have been cases of patients as old as 17 years of age revealing their human tails to doctors for the first time because the tails have eventually begun to cause them pain.” [10]
While some creationists may find it challenging to reconcile this with their beliefs, the scientific consensus supports the idea of evolutionary processes leading to such variations.
Citations:
[1] https://en.wikipedia.org/wiki/Human_vestigiality
[2] https://www.britannica.com/list/7-vestigial-features-of-the-human-body
[3] https://byjus.com/biology/vestigial-organs/
[4] https://www.discovermagazine.com/the-sciences/5-vestigial-body-parts-found-in-humans
[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4378721/
[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5879970/
[7] https://pubmed.ncbi.nlm.nih.gov/29315541/
[8] https://onlinelibrary.wiley.com/doi/abs/10.1111/joa.12774
[9] https://www.sandiegouniontribune.com/sdut-tale-of-the-tail-disappearing-act-before-birth-2007feb18-story.html
[10] https://www.webmd.com/baby/what-is-a-human-tail