Buzz
The phrase 'eating with your eyes' typically refers to how we judge and enjoy food visually before tasting it. (Interestingly, the look of food and even the dish it’s served in can alter how we perceive its flavor.) However, when it comes to frogs, this phrase takes on a far more literal meaning.
Researchers and nature enthusiasts have long observed that frogs and toads close their eyes tightly, sometimes retracting them into their skulls while swallowing. This behavior, scientists suggest, helps the amphibians push food down their throats. Essentially, their eyes act like a compacting mechanism. As biologist Mary Dickerson noted in 1906, 'As odd as it sounds, the toad’s large eyes can press down into its mouth, aiding significantly in the swallowing process.'
While this may sound bizarre, it’s also fascinating. However, this theory remained untested until 2004, when a group of biologists at the University of Massachusetts decided to investigate the role of a leopard frog’s eyes during feeding.
X-ray footage captured during feeding time showed that the frogs' eyes retracted into their mouths, 'making contact with the prey and seemingly pushing it toward the throat.' Measurements of electrical activity in the eye retractor muscles confirmed that this movement was deliberate and not caused by pressure changes in the mouth. Additionally, when researchers severed the nerves controlling these muscles, the frogs could still swallow but required nearly double the effort to move food down their throats.
The findings indicate that frogs' eyes play a crucial role in swallowing, assisting the tongue in guiding food toward the throat. This assistance becomes even more significant when the frogs consume larger prey.
