A question about lion's manes -- regional or individual variation?

I have a question about lion’s manes. I know that not all male lions have the stereotypical magnificent, luxurious mane – some of them are sparse and scruffy.
I wonder, does this trait just very between individuals, or is there a regional variation : “Lions from ‘Area X’ tend to have thicker mans than lions from ‘Area Y’ ?”

Both, and it runs in “families” so to speak.