Why do frogs blink when they swallow?

The frog is an expert at catching insects. It squatted on the edge of the pond, motionless, and stared at the various small insects flying towards it, without any expression. Suddenly, the frog leaped up like an arrow from a string, and its whip-like tongue rolled out of its mouth, eating the insects into its mouth, and it never missed. What's more interesting is that the frog blinks every time it swallows food; the larger the food it swallows, the more times it blinks, until all the food is swallowed. What is the reason for this?

The frog has a wide mouth. It uses its long tongue to stick to the flying insects and then put them into its mouth. Frogs have no teeth and can only "swallow the whole food". There are no bones at the bottom of its eye sockets, and there is only a thin membrane between the eyeball and the mouth. Every time the frog swallows food, the eye muscles will contract, producing this blinking action; at the same time, the eyeball will protrude toward the mouth, forming a pressure that pushes the food into the esophagus. In this way, the frog will often blink whenever it swallows.

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