Dunno, but they are both rodents, so once in the stew...............
I used to hunt squirrel and rabbit and grouse as a kid. My older brother never tried the squirrel. “That’s just a rat with a furry tail!”
I’m guessing that a squirrel eating nuts and whatever in the woods tastes a lot different than a rat caught while foraging through the garbage in an alley. Farm rats might be okay with a feast of various grains on their menu.