Vestigial Tail (Human Tail)

A vestigial tail, or human tail, is when a baby is born with soft tissue sticking out of their lower back. The tissue looks like a tail. The condition is very rare, with as few as 60 documented cases in more than 100 years. It doesn’t affect babies’ overall health. Very rarely, the condition may be a spina bifida symptom. Most babies born with vestigial tails have surgery to remove the tissue.

Types of human tails

Healthcare providers may say your child has a true vestigial tail or a pseudo tail. The difference matters, since pseudo tail may be a symptom of issues with your baby’s tailbone. A true vestigial tail is made of fat, connective tissue, muscle, blood vessels and nerves. A pseudo tail may contain part of your baby’s spinal cord, bone and cartilage.

Symptoms of vestigial tails

The condition symptoms vary. It may cause tissue to form a tail just above the groove that separates your baby’s butt cheeks. The tail may look like a finger, a sausage or a tiny elephant’s trunk. Vestigial tails can be up to 5 inches (13 centimeters) long. The tail may move. In some cases, the “tail” is a swollen area or small bump in your baby’s lower back.

Vestigial tail causes

This condition happens when something interferes with how a fetus’s spine forms during fetal development. All fetuses have temporary embryonic tails. Normally, fetal tissues absorb the embryonic tails, which become part of fetuses’s tailbones. But sometimes, that doesn’t happen, and your baby is born with tail-shaped tissue outside their body.

How doctors diagnose this condition

Sometimes, a prenatal ultrasound may detect something sticking out of a fetus’s lower back. But healthcare providers usually diagnose this condition soon after birth.

If your baby is born with what looks like a tail, their healthcare team will do MRI scans and ultrasounds to confirm the tail isn’t a pseudo tail. Those tests are also how providers check for medical issues that can happen with a human tail, like spina bifida.

Is there a cure for a true vestigial tail?

Surgery to remove the tail cures the condition. A surgeon will make a cut (incision) around the base of the tail, remove the tail and close the incision.

When should I seek care?

Typically, healthcare providers diagnose a vestigial tail soon after your baby is born. They may recommend that your child have surgery while they’re still very young, particularly if the tail is noticeable. There are reports of older children or adults seeking care for a human tail. In those cases, people seek care because the tail makes sitting painful. Having an unusual condition, like a vestigial tail, may cause self-esteem issues.

What can I expect if my baby has a human tail?

That depends on the type of tail that your baby has. A true vestigial tail isn’t a serious medical issue. If the tail is a small bump on your baby’s lower back, you may decide against surgery to remove it. Surgery to remove a tail cures the condition.

The situation is different if your baby has a pseudo tail, which may be a symptom of issues with your baby’s tailbone. In that case, your baby may need other treatment to manage the condition.