http://en.wikipedia.org/wiki/Horses
OK, well, I see some definition here besides height.
It still seems nebulous why they would differentiate between “horse” and “pony” based on a few key features (including that ponies tend to be greater volume/surface - fat - just like this little so-called “horse!).
Sometimes I find horse people just nuts! But not as nuts as dog people. ;-)
6000Horsepower
100 HP
Howzbout the cat people?