They occur in around 80% of Asians, and 80% to 85% of Native American infants. Approximately 90% of Polynesians and Micronesians are born with slate grey nevus, as are about 46% of children in Latin America, where they are associated with non-European descent. These spots also appear on 5–10% of babies of full Caucasian descent. African American babies have slate grey nevus at a frequencies of 90% to 96%.
What’s wild is us humans are stripped and spotted, like cows, but you can only see it in ultraviolet.
They’re called Blaschko’s lines and they’re invisible to our eyes.