“Innies," “Outies" and Other Belly Button Facts

Most of us have innie belly buttons, with only about 10 percent outies. A few of us may have something in between, or even a little of both! Here are some more fun facts about our belly buttons.

• Belly buttons are scars marking the spot where we were connected to our mothers by the umbilical cord during pregnancy.
• The shape of your belly button has nothing to do with how the umbilical cord was cut or clamped when you were born. It’s a common myth, leaving dads and doctors to get the blame for the occasional outie. There are two reasons why some of us have outies: 
  • There’s simply a bit of extra scar tissue, or 
  • We have an umbilical hernia, which just means that the abdominal muscles didn’t knit together properly after the cord fell off, so a little bit of tissue pokes through the hole. 
• The Belly Button Biodiversity project discovered more than 2,300 species of bacteria in the 60 belly buttons tested—1,458 of which had never been discovered before! The average number of bacterial species per belly button is 67, though innies tend to have more bacteria than outies.
• All mammals have belly buttons except for the platypus because it lays eggs.
• Belly button lint is made up of bits of clothing mixed with your skin cells, dirt and bacteria. Men tend to have more lint than women, probably because their belly buttons are usually hairier.
• The fear of belly buttons is called omphalophobia. If you strongly dislike anyone touching your belly button, or you feel anxious or nauseous when you see someone else’s, then you may have omphalophobia.
• In 2010, an Australian named Graham Barker was awarded the Guinness World Record for the largest collection of belly button lint. At the time, he had collected 22.1 grams of his own lint over the previous 26 years.
• Just like our fingerprints, no two belly buttons are exactly alike, so celebrate belly button diversity!