My elephants have trainable intelligence "Advanced" and they can be trained in haul. I looked for some small and cheap hauling animal and monkey was marked as "Advanced" aswell; after taming it I cannot train it in hauling.
I seem to remember from Alpha that wild board could haul but now they are marked as only "Intermediate" which would mean that they cannot be trained in haul (haven't checked that yet, gotta tame one first).
I believe it's not intentional since animals of the same intelligence can train different skills.
Edit: Wild boar cannot haul either, so I guess it's trainability state is correct.
There's also the matter of body size. I believe monkeys are simply too small to haul. Same with, say, Yorkies.
I thought if animal's trainability was advanced and its carrying capacity existed, it would be able to haul. My bad then. ;<
Basicly you right, but they add the bodysize depence last version or A17.
To reflect that not a small animal should be able to haul an elephant/Centiped corpse.
I mean, still feels like a bug though that such a thing can be so easily misunderstood. It'd make more sense to me if things simply said "Trainable: Release, Rescue, Haul" or "Trainable: Release" or whatever.