Apparently, not all mammals respond to cannabis. Like cannabinoid receptors are not in all animals, or their brains don't have the parts that react to cannabis. Brains are too small . Some not all. At any rate I doubt it's harmful. I k ow a few dogs that take doggie lorazapam (Ativan) for heir nerves and another dog that has a Codiene prescription for pain. So I guess they respond to some meds. Maybe cannabis too. Mold arthritic dogs would love some weed for inflammation and pain. Especially in the mornings.