A professor of evolutionary biology explains: “We inherited the major nerves we use in breathing from fish. We became heir to this design from fishy ancestors with gills closer to the neck, not a diaphragm well below it. The characteristic pattern of muscle and nerve activity of hiccups occurs naturally in other creatures – more specifically, they turn up in tadpoles that use both lungs and gills to breathe. When tadpoles use their gills, they have a problem—they need to pump water into their mouth and throat and then across the gills, but they need to keep this water from entering their lungs. So what do they do? They shut the glottis to close off the breathing tube, while sharply inspiring. In essence, they breathe with their gills using an extended form of hiccup.”
When COVID scrambles your sense of smell
Ryan McManus writes about how COVID caused “parosmia” or a screwed up sense of smell: “When you smell something, anything, the olfactory nerves capture the scent molecules as encoded data, and pass that data signal along to your brain, which decodes it and matches it to a known scent, like chocolate or feet. With parosmia, the data of the coffee smell gets garbled and turns up in the brain as something totally unknown, like scrambling a QR code. And, at a survival level, a good default for “this smell is unknown to us and confusing” is “stay the hell away from this”. This was unpleasant for me but downright crippling for others, who find not only food but their romantic partners or their own bodies smelling repellent, and no amount of hygiene will cover the smell.”
Continue reading “We hiccup because we’ve forgotten that we aren’t fish”