Most mammals seem fine with shorter hair (usually denser though). The only other case that comes to mind of very long hair restricted to a specific body area is that of horses manes, which to be fair I’m also not totally sure what purpose it serves. Many equines seem fine with shorter manes and tails that don’t have such long hair, like zebras. They swish flies away all the same.
Some animals have long hair but it covers most of their bodies (like llamas or yaks maybe), it’s not restricted to a small area. Other animals have denser or longer hair in some areas, like lions, but this serves a purpose (protection of the neck and head) and even then the length ratio between these longer hairs and the rest of the fur isn’t as skewed as that of humans.
So, why? I get that hair on the head helps protect it from the elements and sun, but why so long? Some humans can grow hair longer than their own body length, which is remarkable, and without doing any fact check I’d say we are probably among the top 5 species with longest hairs ever. Is it just a showoff feature like a peacock’s tail feathers, an indicator of overall health? Or does it serve another function as well?
I didn’t mean to type this wall of text…, thanks for coming to my TED talk
Way I figure, the common traits for any given part of the world where as much influenced by the isolation of groups as environmental factors. Back in primitive times it could take months wandering before you happened across another group, and even then there may be ‘untrusted tribe’ type conflicts.
It still shows up today in how rural isolated communities tend to foster more prejudiced attitudes towards people different from them. But now we can move all over quickly and communicate instantly, so there’s a less concentrated effect by location. Plus the whole advent of ordered society and the host of factors that brings into play.