Laut FAQ:
Q: The bestiary seems to be missing the different types of horses and ponies that are listed in the 3.5 MM. What should be used for things like Warhorses and ponies?
A: (James Jacobs 12/2/09) We provide stats for a Horse (the Large version) and a Pony (the Medium version), so that Small and Medium creatures would have these classic animals around for mounts or pack animals. We probably should have been more obvious about this in the write-ups for the horse and pony in the Bestiary, I guess.
* Light horse = horse
* Heavy horse = advanced horse
* Light warhorse = horse with combat training
* Heavy warhorse = advanced horse with combat training
* Pony = pony
* Warpony = pony with combat training
* Donkey = pony
* Mule = advanced pony
* Camel = horse
The camel's sort of a special case, since it DOES have some different characteristics from the horse. And as a result, I'm relatively sure that camels will be showing up in the Bestairy 2. But until then, just using horse stats should work fine.[Source]