But if you get to eat it, why can't I?

Your dog is a miracle of nature; not only is every pooch on the planet descended from wolves—apex predators with a social intelligence rarely seen outside primates or cetaceans—they've co-evolved with modern humans (sometimes because we bred them, sometimes by accidental selection) to understand us in ways chimpanzees can't even fathom.* Your best friend, however, is also an idiot who will poison him/herself at the first opportunity by eating human food that it cannot eat. A lot of these surprise poisons are fruit, because its ancestors were not tree-dwelling sugar junkies like ours. They still want to eat it, though, because A) food, and B) they want to do whatever you are doing. So consult this handy chart from Ohio State veterinarian Dr. Edward Cooper to see if you should let your dog eat that blueberry you just dropped on the floor. (Note: Not included are tomatoes. I guess vets ascribe to the official dogma that those are vegetables. Nevertheless, don't let your dog eat tomatoes.)

Sources: E.W. Scripps