Here's why:
* Holding prey: Recurved teeth allow snakes to grip and hold onto their prey firmly. As the prey struggles, the teeth dig in deeper, preventing escape.
* Swallowing large prey: Since snakes can't chew, recurved teeth help them pull their prey into their mouths. The backward angle allows the prey to be swallowed whole, even if it's much larger than the snake's head.
* Digesting prey: The angled teeth also help to tear and shred the prey, facilitating digestion.
So, the teeth don't curl backwards, they are angled in a way that maximizes their effectiveness for hunting, swallowing, and digesting.