Cloaca may be one of the prettiest sounding words in the English language, but it is one that few people are offhandedly familiar with. It is derived from the Latin “cluo,” which means “sewer,” which is highly appropriate, as a cloaca is a catch-all orifice through which urine, feces, and eggs pass. This biological feature is present in all species of birds, but is not found in mammals, save for one unique exception — the monotremes.
A platypus or echidna definitely makes for a tattoo as interesting and unique as the creatures’ own status in the mammalian world. Let us all give thanks to these odd mammals, because if God hadn’t learned from the mistakes made in their creation, we could all be going through life shitting and pissing out of the same hole we occasionally lay eggs from.