Rig animal model as humanoid?

Newbie question.
Suppose I have a 3d model of an animal like a horse.

I want to rig that horse with a humanoid avatar and make it walk on two legs and do humanoid stuff.

Do I need to re rig the model e.g. in Blender, like put it in T-pose etc and rig it that way? Or is there some easier way?

 

If you are trying to make an animal walk like a human....

Yep. This might be the better way to do it.