Another easy achievement to do in maybe 15 minutes.
Look for the orange paw print on your map, travel to it and start the beast kill. You will be killing beasts, anywhere from 3-9 in the ones I did. Only semi hard ones to do were the wolves who kept running away because I had the Bloodfang Sabretooth with me, can be easier to dismiss your beast and go after them alone, though I just sent Bloodfang after them, they eventually ran back towards me and an arrow would usually finish them off. 3 badgers did manage to kill my Bloodfang though, those guys are little demons.
Do this 5 times and the achievement will pop.