It does sort of look like a track, as though some sort of critter was chomping its way along. It looks as though whatever it was just ate deep enough to scar the surface without eating all the way through the skin.
If there are only one or two like that I wouldn't worry about it. If there are quite a few you might check with your county Ag people. They'll be in the phone book. You'll probably have to take some in to show them.