Did you know that iguanas shake their heads generally as a defensive gesture? They also do this to show discomfort, stress or irritation.

please bluesky, let me post videos of reptiles...

Don't let this fool you, this reptile is a lizard, not a snake. This is the Anguis fragilis, one of the many lizards that lost their limbs. We know that this is a lizard, and not a snake, because of some traits like the eyelids and the capability to do autotomy, and also the tongue is not forked.

Many people see this and think that the snake is yawning because it's sleepy, but actually, snakes do this after feeding because of the structure of their jaw. Unlike ours, snakes jaws aren't connect by a bone, wich makes them able to eating things much larger than their heads.