In plantigrades (e.g. humans, bears, most rodents), the entire sole of the foot touches the ground, in digitigrades (most carnivores, most birds), the heel is off the ground and unguligrades (ungulates) walk on hooves.
It is one of at least five forms of locomotion used by snakes, the others being lateral undulation, sidewinding, concertina movement, and slide-pushing.
It should be noted the linked article is actually titled "Carnivore & Ungulate Locomotion" and is about running on limbs. Really cool overview, actually
Damn, good point. Couldn't come up with a counter-example so just copy/pasted off of Wikipedia verbatim lmao
Look out for tomorrow's TIL when I look up what that type of locomotion is called lol
Actually, I'm really at a loss at what to call this paraphyletic group; tetrapods come to mind but they technically still include snakes...
Modified plantigrade? Close relatives like skinks are plantigrades and some snake species have vestigial hind limb protrusions that are basically highly-modified femurs.