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
I think many see evolution as a smart process moving towards something or as improvement. That’s correlation, it looks that way from the outside, but evolution is merely what survived long enough to reproduce most, and traits best for that and/or selected by a partner, are what get passed on.
And back to OPs question : maybe long hair was helpful? Either in finding a mate or keeping warm.
I’m bald AF though, and successful on both counts so what do I know?
You aren’t subject to every pressure every hominid ancestor ever was. Bald today still gets you laid, congrats! And you got hats to keep warm and look fabulous. :) I believe long hair must have presented some kind of advantage at some point though, there are some interesting comments here.