system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we hiccup?
gpt
This is a surprisingly great question.

It may be related to a time when our ancestors were sea creatures transitioning to living on land and it may represent a reflex to help clear our breathing system of water.

Or, it may be a reflex that mammals developed to help get air out of the stomach; air introduced when suckling - something that mammals do and no other kind of animal does (and only mammals, as far as we know, hiccup).