Interestingly, the percentage of people with this mark varies by region:
Africa: About 10% of the population, the highest rate globally
Asia: Around 4%
United Kingdom: Approximately 0.9%
United States: About 0.1%, the lowest reported rate
Some theories suggest that this small opening could be a remnant of structures similar to gills from ancient ancestors, hinting at humanity’s evolutionary link to aquatic life.
While this idea remains a theory, the mark itself is completely normal—and simply another fascinating detail of human biology.
