It’s alive! Rock on the outside, guts on the inside

A rock full of blood and guts – it’s got nothing on a kinder surprise. Except that it’s not a rock at all, but an underwater oddity that may well be your great great great great great grandmother. And probably resembles what that shriveled old lady would look like too.

But eww, what even is it?

Photo: Arvid Puschnig
Photo: Arvid Puschnig

This creepy creature is actually called piure, (p.chilensis) and it’s a species of tunicate, animals called so because they’re incased in a tough, non-living tunic. (Some people wear a similar thing but that’s another issue). It’s this tunic that disguises piure as a rock, but remove the costume and you uncover one of the earliest animals in the chordate line.

And who’re chordates? Basically all the animals that first come to mind, mammals, amphibians, reptiles, birds, fish, HUMANS. So maybe they’re not exactly your heaps great grandmothers, but they share one of our most ancient ancestors – so they may have given rise, to us!

What do they do?

Well in keeping with their rock persona, not a whole lot. They’re sessile animals that filter feed, meaning they just sit around in one spot, eating bits and bobs out of the water.

They’re found off the coast of Chile and Peru and are, believe it or not, eaten by the locals. The taste has been described as bitter and soapy, so if you can get past their appearance and pop one in your mouth that’s what you’ve got to look forward to.

Photo: Arvid Puschnig
Photo: Arvid Puschnig

And do they rock each other’s worlds?

Piure has a pretty bizarre sex life. They start off as males and then go on to decide one gender isn’t enough and develop both lady-like and manly gonads. When it’s time to make babies they shoot both their eggs and sperm up into the water, hoping they bump into each other and fertilise.

And the result of this fertilisation? Not a mini meat rock, but a tadpole like larva, which goes through metamorphosis before it comes full circle and resembles the freaky living rock of it’s parent.

A living rock full of red goop, that people eat.

Enjoy your dinner, will you be having tomato? Love O.O.

Photo: Wiki Commons



Manríquez, P. H., & Castilla, J. C. (2005). Self-fertilization as an alternative mode of reproduction in the solitary tunicate Pyura chilensis. Marine Ecology Progress Series305, 113-125.

Roman, D. A., Molina, J., & Rivera, L. (1988). Inorganic aspects of the blood chemistry of ascidians. Ionic composition, and Ti, V, and Fe in the blood plasma of Pyura chilensis and Ascidia dispar. The Biological Bulletin175(1), 154-166.


  1. So, I stayed on the island Tobago when I was maybe 4 or 5 and I have all these vague memories of it… and there was this one meal I remember and could never fit to any known food. Until now??

    Sadly I don’t recall what they tasted like.


    • Oh my goodness that is so cool! Apparently they taste like a soapy metal haha – do you recall it tasting as delicious as that sounds? 😛


Let me know what you think!

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s