Ooohkay... Disclaimer: I'm playing Devil's Advocate here. I got curious on the subject and did a bit of research.
According to one veterinary website, the minimum reported oral lethal dose of THC was >3g. Marijuana usually contains between 1% and 5% THC, meaning 60g to 300g. That's 2 to 10 ounces, give or take. Hashish was reported as ~10%, meaning 30g (over an ounce of hashish). Given the wide variation of sizes of dogs, and this being a minimum reported oral lethal dose, that's a LOT. I can only imagine a larger dog would have a much harder time overdosing to that point.
I have known people with pets that did enjoy either stealing their stash or smoking it with them. I'm not advocating this, I'm just saying that these dogs went out of their way to do so. I know someone with a toy chihuahua that was a habitual marijuana thief. He would sneak around, out of sight, hop up on the couch to the table, grab it and run. This dog weighed less than a pound, and probably stole up to a sizable portion of his body weight on one occasion. He loved it. I'm mentioning this because I've seen the same logic applied to animals as applies to humans - if given the option many will make a choice. I had another friend who's dog, if he smelled smoke, would make his way to the living room and calmly sit down and wait his turn. He'd snuggle up to his owner, wait for one hit, then go lay down across the room with a huge grin on his face. I'd hardly view that as force or coercion.
Another fact I found while researching this was articles referencing that inducing vomiting is difficult after 30 minutes, due to the medicinal properties of marijuana preventing the vomiting. This is a drug that the government claims has no medicinal purposes, yet here are PhDs trying to fight against this medicinal purpose. Ironic, no?
I have also heard of someone giving stems to a small fuzzy as a chewing item. This I am thoroughly against - as ingestion seems to be the only way to OD to the point of death. As well, especially in the case of chinchillas, it's true that the hind gut fermentation is so easily disturbed, it's a chance never worth taking.
Where I am going with this is that it effects animals differently just as it affects people differently. Some people love it. Some people get nervous and jittery. If given the option some pets seem to enjoy it, others (and I have seen this too) will simply back away, leave the room, or by simple mannerisms decline the offer. Humans have a choice (just not legally) and some animals make that choice too.
And I'm done playing devil's advocate.
I am NOT suggesting anyone go and get their dog high, much less their small fuzzies, but I figured I would stir up what was otherwise a rather one-sided discussion.
I'm going to go hide now until the dust clears.
