Each time a frog swallows, his eyes close. The eyes depress down into the sockets to help move the food down his throat. He can swallow food without the assistance of his eyeballs, but being able to push the food significantly reduces the amount of swallowing he’ll need to eat his meal. He can close both eyes, or one at a time as needed to help force down food. His eyes don't do all the work. He’ll use his front legs to help force his prey into his mouth, and his tongue assists his eyes in pushing it towards his stomach.