Generally I think if it's on both sides, it's either by accident or because it is very thick, if I'm not mistaken? I'm not sure it's ever done on purpose...that horse pictured looks like he has just a naturally short, thick mane (or was cut short and grew out) and it's left alone. It also looks to be based on the left side of the neck, with much of it directed forward and he may not have any hair on the right side (when he is standing still without wind), it's hard to tell.
Or do you mean a grown out roach/mohawk look?
My gelding has a modate-thickness mane which was roached, and as it grew out it mostly stuck straight up but would flop side to side as he moved. Eventually when it grew it naturally laid over as it would naturally like to, different sections picking different sides. Is that what you're referring to?
I'm confused whether you mean that the whole mane parts down the middle or if different sections lay over on different sides.
Last edited by rocky pony; 09-06-2010 at 05:18 PM.