Of course mice are inportant for snakes. There is not a huge difference in the nutritional value between rats or mice but one or the other is a must. I prefer frozen because live food can attack and harm the snake. It can also teach a snake to hunt and can pose a threat to you when handling your snake. Some snakes prefer male mice to females and some wont touch all white mice. Some snakes wont touch dead food at all. It depends on the snake.