I just had an initial consultation at a TMJ specialist clinic at the University of Minnesota. During my evaluation, the specialist told me that 40-50 mm is how wide the average person (and "normal" jaw) can open. I, like other people with hypermobile joints, can open my mouth comfortably, without strain, to a solid 55 mm.
They open it very wide.
You can't. You can only open your mouth as wide as your jaw will let you.
A mouth prop is a safety device used by dentists to keep the mouth wide open when they perform a procedure. It is also sometimes known as a bit block.
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.
roughly 65 degrees
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