Jockeys as Riders: Could it Happen?

I've often wondered if horse racing jockeys could make it in the motocross world. It seems as though they would have some advantages over the average Joe that's considering taking up racing. Jockeys are short and light-weight, having trained their selves to maintain a strict, airy weight and still function at semi-normal levels. They're accustomed to holding onto a fast-paced "thing" between their legs. The good ones have an edge about them that makes them seem bigger than they really are.

I still wonder if they would make for a good motocross racer...