It's foods butchers would otherwise toss out, it has nothing to do with hunting rodents.
An annoying reality, freaking ox tails are 5.99 a pound. My folks used to make it because it was there, now I it's pretty expansive for the amount of meat you get. I still make it and tongue to partly freak out friends, but also because I grew with a taste for it. A freaking beef heart is nearly impossible to get for me. The sort of even local butchers we gave here, you get a strange look and a 'I can get it, but not sure the price'. Which to me is too expensive to bother, than get just a NY or a London broil...