A baby boy in Brazil has been born with a rare ‘true human’ tail, measuring an incredible 12cm, with a 4cm ball-shaped mass at the end.

The rare congenital anomaly was discovered when the mother gave birth at 35 weeks, after going into premature labour. The mum had a healthy pregnancy, suffering just one urinary tract infection. She didn’t drink or use drugs, but was smoking 10 cigarettes a day.

According to the Journal of Paediatric Surgery, the tail was discovered when the baby was born. Babies born with true human tails are extremely rare, with only 40 cases ever reported.

Baby born with human tail

Baby born with tail

The tail was examined, with doctors finding a ‘single umbilical artery and the presence of a rounded fibroelastic appendage of approximately 4 cm in its largest diameter, supported by a 12 cm fibrous cord in the left paravertebral lumbosacral region.’

Doctors investigated for possible neurological issues, but the baby was given the all-clear. The tail was removed without any complications.

How did the human tail form?

Baby born with tail removed

At about the fourth week of gestation, babies start to grow a tail, which usually disappears by around the eighth week. It eventually becomes our tailbone.

“Human tails are classified as true and pseudo-tails,” the report explains. “The real ones represent the persistence of a remnant of the embryonic tail formed between the fourth and eighth week of gestation, being composed of adipose and connective tissue, blood vessels, muscle and nerve fibres. Pseudo-tails are protuberances basically composed of adipose or cartilaginous tissue and the presence of bone elements. True human tails are very rare.”

Removal of baby tail

A post-surgery investigation of the tail found it was made up of boneless tissue, while the ball was simply fat and embryonic connective tissue.

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  • Poor little mite having to have surgery at such a young age. I hope this doesn’t affect his future.


  • Well, there ya go. What a unique little bub


  • Would never have expected that to appear on a new-born. Thank goodness it didn’t affect him and was removed with no complications.


  • I never saw this kind of thing before.


  • This looks quite unusual. Not what I was expecting.


  • I’ve never heard of anything like this.


  • I’ve seen a baby with a little nub at the base of the tail bone that looked like a tail but nothing like this!


  • Oh wow that is insane. Never seen anything like it. Glad baby is ok though


  • Very Trippy !


  • Very invasive to be sharing this, I hope the parents were informed prior to publication


  • Never heard of this before!


  • WOW! I had no idea. I’ve never heard of this.


  • That’s one creepy looking tail!


  • Very rare indeed ! Glad it could be easily removed without complication


  • Definitely a positive that the tail was able to be successfully removed without consequence! There’s so much about human biology that’s fascinating and the womb is a magical place. But by the same token there is so much that goes on and that is completely beyond our control.

    What a story to have though!


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