Why do some snakes bite prey and then follow it instead of holding on?

Some snakes bite their prey and then follow it rather than holding on because their venom acts slowly. By biting and retreating, the snake avoids potential injury from struggling prey while the venom takes effect.1

Once the prey has succumbed, the snake uses its tongue and Jacobson’s organ to trail the scent of the animal until it locates the stiffening body. This behavioral strategy is distinct from other methods, such as constriction or the rapid immobilization seen in snakes with faster-acting venom, which may hold onto their prey to prevent it from escaping.1