Hiccups occur because muscles between your chest and stomach suddenly tighten. This causes you to breathe in very quickly. The air is stopped in your throat by your vocal chords creating the sound of a hiccup.
The causes of hiccups include eating or drinking too quickly; a sudden change in temperature in your stomach or in the room; shock; stress or excitement. Some people can have hiccups for months or even years at a time, but scientists don’t really know why this happens!
Hiccups are very weird. When we hiccup our bodies are trying to breathe in and out at the same time! No one truly knows why are bodies are capable of doing this!
A lot of other animals get hiccups to and even human babies get them when they are in the womb.
Some scientist think that hiccups are an evolutionary hangover. It has been shown that tadpoles during their development can breathe both air and water – they have both lungs and gills at the same time and they hiccup as they do so, so maybe it is done to stop water getting into their lungs?
And as ancestors of humans and apes (and all animal life) started out living in the sea millions of years ago maybe it’s something to do with that?!