It seems you can win this cute new Darkmoon Faire pet by winning the race in under 20 seconds. I was able to consistently beat the race in about 13 seconds but had no pet. *frown*
It turns out that each month some new item will be awarded for getting a good score on the race, one of these months will be the Minizep, but apparently not this month. So if you are wondering why you keep racing but are not awarded anything, it is by design as far as I know.