Ever try cutting your hair with a knife ? I just tried it and it ain’t easy. Photos and pictures of historical Africans never show them with an Afro so presumably they’ve been cutting their hair long before they acquired scissors or steel knives.
Can you cut your hair with stone ?
Why do depictions of early long haired homo sapiens, presumably in Africa, never show Afros? Have the scientists determined that the alleles responsible for African hair came later?
Super curly African hair is very fragile, and doesn’t get long without a lot of maintenance. Every bend in a hair is a weak spot, that will snap off easily, and of course, African hair has lots and lots of spirals. Also, the natural hair oils have a harder time traveling down the spirals, so it takes some effort for a person with what we think of as African hair to grow an afro.
They probably used sharpened edges of reeds or other kinds of plants (which primitive peoples still use). There are some plants that have such sharp blades that they can draw blood if you’re not careful.