Because they don't need to ^^? It is a bit mind-boggling, but family names do not exist everywhere. e.g. in Indonesia, the people have multiple names, but no such thing as a family name (= a name which multiple family members share) exist. I also recently learned that apparently Mongolians only have a single name. My colleague told me about a Mongolian guy he knows from a conference. Normally that guy just signs up for conference and other things with his name for first and last name. Looks stupid, but there's not really another way. We talked about this topic recently, because my colleague was looking at a research paper published by this research group, with like 4 people on there only identified by a single name. Yes, it's weird, but this exists and is alive. EDIT: Seems I'm wrong about the Mongolian names, but the situation is a bit complicated, https://en.wikipedia.org/wiki/Mongolian_name#Mongolia .