When locals in Cuiabá, Brazil came across a snake with an overly-distended belly, they performed a dissection to see what enormous meal the snake had eaten. The answer? A fully grown pitbull.
Snakes are able to swallow animals much larger than their heads because of their flexible jaws. While humans have strong jaws to eat hard foods, their jaws are able to stretch and accommodate large meals.
It is a common myth that the snakes actually detach their lower jaw to make room for food. Their lower jaw is actually two bones that connect in the middle with a very flexible ligament. Each side is able to spread out independently to allow the food to come in.
WARNING: Video is very graphic.
Hat tip: i09