Black grapes also go by a few other names such as slip-skin grapes and also Concord grapes.
This fruit can be used to make jellies, juices, jams and also just eaten fresh.
So can guinea pigs eat black grapes at all?
Yes, but only one or two at a time and not very often as they have a lot of sugar content.
If you were to give too many of these grapes to your guinea pig it would cause them to possibly get sick.
Additionally make sure the black grapes do not have any stones in them as it could possibly get lodged in their throat and make them choke.