A lone, old, wise wolf was walking through the snow on a blistery, cold winter's night. The wolf had not eaten in several weeks, and was on the verge of starvation. He was terribly thin and hungry. He soon came upon a pasture with a herd of sheep inside. Several sheep would provide the perfect meal, plump and promising. The wolf might not get another chance to eat for days. In his thin state, the wolf could easily slip through the fence surrounding the pasture and kill as many sheep as he pleased. But when he finished eating, he would be too big to slip through the fence again and the farmer might find him stuck in the pasture with the sheep.
How did the wolf manage to eat as many sheep as he liked and not be caught in the pasture by the farmer the next day?