What's a Boa?
There's more than one kind of boa, and they're not all giant-size like the boa constrictor.
The boas (including pythons and anacondas) evolved about 80 million years ago from "big-mouthed" reptiles, the early snakes that could swallow large prey.
That's Stretching It
Of all snakes, boas can open their mouths the widest—to swallow seemingly impossible mouthfuls. Bone anatomy and elastic ligaments that connect jaw bones allow the big stretch. How wide can you open your mouth?
Closed jaw at rest.
Open jaw, with a 120-degree gape.
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