If it’s just for your own use, then you can define predator however you like. But generally it’s an animal that kills and eats other animals for food. A snake that kills an animal and doesn’t eat it is not a predator of that species. More narrowly, predator is usually applied to larger animals that eat vertebrates. Few people would refer to a robin as a predator because it eats earthworms.
And not just in one accidental encounter. Conceivably an animal like the sea otter might have killed and eaten a raccoon in the last 10,000 years, but to call it a “natural predator” of the raccoon is stretching it, if you ask me. What exactly is the use of such a classification? We might as well include crabs, bats and anteaters.
smthsmb: I think I would exclude feral pigs from the list because they are a feral domesticated animal or an invasive species species if descended from the European Wild Boar. I would guess that many feral pigs in North America are descendants of both. Nonetheless, I do know the are ferocious and destructive animals.
Beckdawrek: The criteria excludes parasites.
Guizot: The 10,000 year time frame was not completely arbitrary. 10,000 years excludes most of the megafauna that disappeared during the most recent mass extinction event in North America. Crabs? Now you’ve got me thinking. What’s the biggest North American crab?
The line between herbivore and omnivore is a blurry one. Many animals considered herbivorous have been observed eating meat. Often carrion, but not exclusively - I’ve personally seen a mule deer pick two song sparrow chicks from a nest and swallow them.
10,000 years makes it a little hard, too. Some of the megafauna was still around at that point, so there will be a lot of fuzziness around things that went extinct in right about that same timeframe.