Some folks suspect that the green dwarf, who has been reported by several people, is connected in some way with the mutilations. But many others don't believe in green dwarfs.
seriously, who in the world would want to, or could do what is evidenced at these scenes? surgical precision, no blood, no tracks. odd lights often reported.
many ranchers in the US were patrolling their land armed because they had lost so many cattle to this occurence.
its' weird, but i do not suggest any likely cause, because it is so bizzare.