Apparently snakes have no sense of how much they can swallow.

When I was about 13 I killed a water moccasin and then threw him down in a creek bed. The next day we had a guest that came running up from that same place yelling, "Snake!."

"Don't worry, that snake's dead."

"It's moving."

When I investigated I found another water moccasin swallowing the first. If anything, this second snake was smaller than the first. About four inches of the first snake's tail was sticking out of the mouth of the second snake.

I doubt, had I let him go, that he could have survived the meal.