Buccal pumping
Buccal pumping is a method of respiration using the throat muscles. Animals using this method will typically move the floor of the mouth or throat in a rhythmic manner that is externally apparent.
This method has several stages. These will be described for an animal starting with lungs in a deflated state: First, the glottis (opening to the lungs) is closed, and the nostrils are opened. The floor of the mouth is then depressed (lowered), drawing air in. The nostrils are then closed, the glottis opened, and the floor of mouth raised, forcing the air into the lungs for gas exchange. To deflate the lungs, the process is reversed.
This method of ventilation is inefficient, but is nonetheless used by all air-breathing amphibians and is utilized to a varying extent by various reptile species. Mammals, in contrast, use the thoracic diaphragm to inflate and deflate the lungs more directly.
Common animals that use this method include amphibians, as they lack the diaphragm, the muscular sheet directly below the lungs.