Lungfish

But hiccups do make sense for animals that have both lungs and gills, such as lungfish, gar and some amphibians. They push water across their gills by squeezing their mouth cavity while closing the glottis to stop the water from getting into their lungs. Christian Straus thinks this has persisted into modern mammals, including humans, and that hiccups have adapted to a new use—teaching newborns how to breastfeed. The sequence of movements during breastfeeding is similar to hiccupping, with the glottis closing to prevent milk entering the lungs. He plans to look at the specific areas of the brain that control hiccups and sucking movements, to see if the same nerve cells control both of them.