Other mammals have no contact between their airways and esophagi. They can breathe and swallow at the same time, and there is no possibility of food going down the wrong way. But with Homo sapiens food and drink must pass over the larynx on the way to the gullet and thus there is a constant risk that some will be inadvertently inhaled. In modern humans, the lowered larynx isn’t in position from birth. It descends sometime between the ages of three and five months—curiously, the precise period when babies are likely to suffer from Sudden Infant Death Syndrome.
