That's why I said that traits don't even have to be viable, they just don't have to prevent the propagation of genes. Those are either the result of random mutation, are the result of recessive genes that didn't manifest in the parents and therefore didn't present any bearing on their ability to reproduce, or simply just weren't problematic enough to impact reproduction. There's also the possibility that they're not related to genetics at all. It all depends.
Those traits have clearly not been selected for, though, they've simply been rare enough to be tolerated in the gene pool.
Those traits have clearly not been selected for, though, they've simply been rare enough to be tolerated in the gene pool.