roughly 65 degrees
They open it very wide.
You can't. You can only open your mouth as wide as your jaw will let you.
Open the mouth wide.
Birds
A python can open its mouth very wide to swallow prey, stretching up to four times the diameter of its own body.
Wide open. A gaping hole is a wide open hole. A gaping mouth is one which is hanging open, usually from astonishment.
A snake can open its mouth wide enough to swallow prey that is larger than its own head.
Very wide. Approximately 69m.
A snake can open its mouth very wide, up to about four times the diameter of its body, in order to swallow prey that is larger than its head.
hippos can open there about 3 feet or more depending on the size
He stood there with his mouth gaped open, utterly shocked by what he had just heard.