Either can make them very ill/cause death (in extremely high dosages), but the effects are different. Even if they don’t eat things with the THC psychoactive qualities having been unlocked from heat being applied, they can still “look” like they’re very stoned, when in fact, they’re just very, very sick.

Dogs tend to hide all sick-like behaviors similarly. It’s just one of those evolutionary instinctual things they do to not show weakness that could get them removed from a pack (or so I’ve read).