food
I'll bet if they could make 2,000 pound mules someone would have. I mean a "war mule" would have been far more effective than a "war horse" as they are tougher and smarter. (maybe a war horse is better being stupid?)

I don't remember which but maybe the Donkey has 64 chromosomes and the horse has 62 chromaosomes so they they rarely produce fertile, or complete "species" status. Maybe the size of the draft horse precludes efficient operation with a mix of chromosomes???

Llamas - I'm starting to get a picture of Llama atitude. I think I like them. I hear they can be VERY protective and I'm thinking what 600 pounds of angry agile beast runs up to you and kicks you with 2 sharp nails on 2 toed feet - so whats different from being chased by a dinosaur except for 3 toes? OK one with a small mouth maybe?
Jim