If you're like me and are trying to hunt down your animals to upgrade everything, then you're trying to get 3 star pelts and make sure you are doing with the correct weapon. I have searched countless websites, wrote multiple things down, and come to find out some is wrong.
So this is just a heads up for anyone desperately trying to snag a beaver pelt. Most places classify the beaver as a "medium sized" animal in the game; thus, allowing you to assume you can kill it with a Repeater or Sniper Rifle... This causes the 3 star animal you scouted to lose a star, and there goes your perfect pelt. After much experimentation (AND MUCH FRUSTRATION) I have found that if you head shot the beaver with the Varmint Rifle you do not lose a star and come out with a perfect pelt. The beaver should be classified as a Moderate sized animal and killed with the Varmint Rifle.