You’ve seen pigeons strutting around city squares, but have you ever wondered if they have belly buttons? The answer is yes—sort of. While birds don’t have umbilical cords like mammals, they do have a small scar called an umbilicus where their yolk sac attached during development inside the egg. This mark, often invisible to the naked eye, is the avian version of a belly button.
Here’s how it works: Inside the egg, a chick is connected to its yolk sac by blood vessels. This sac provides nutrients until the chick hatches. After breaking free from the shell, the leftover attachment point heals into a tiny scar near the bird’s abdomen. In pigeons, this scar is usually hidden under feathers, but it’s there—proof that even birds carry a reminder of their embryonic past.
Why don’t we see bird belly buttons? Unlike mammals, birds don’t rely on placentas, so their “navels” are far less prominent. Additionally, feathers and down cover the area, making it hard to spot unless you’re conducting a veterinary exam. Scientists only confirmed this through close study of bird anatomy, often using magnification tools.
The discovery challenges the assumption that belly buttons are exclusive to placental animals. Even reptiles and egg-laying mammals like platypuses have similar scars, though they’re even fainter. For pigeons, the umbilicus is a harmless quirk of evolution, a silent nod to their life before hatching.
So, next time you toss breadcrumbs to pigeons, remember: beneath those iridescent feathers lies a tiny, hidden scar. It’s a reminder that nature loves recycling ideas—even if it means giving birds a belly button they’ll never flaunt. And if you ever feel self-conscious about your own navel, take heart: pigeons have one too. They’re just better at accessorizing around it.
