A manticore, a mythical creature with a man's head, a lion's body, and a dragon's tail.

11 Parts of Your Body Another Animal Invented

On the evolutionary histories hidden within your anatomy


Wherever you are, if you look up and watch a scrap of cloud drift across the sky, you are seeing through the complexity of 600 million years of work. This was a collective architectural, scientific, bodily effort. Jellies did it first, clustering opsins, but plants, too, knew the light was there to be seen and saw it, in their fashion. Your camera-like orbs are so complicated that Darwin nearly conceded that gods may have made them, but they began somewhere with your jawless eely vertebrate ancestors pushing through the dark.


I heard it was early, and came from a worm. Or a slug-like creature that scratched at the microbial surfaces for food. There is fossil evidence of a tubular heart positioned near the back of the body, coming down from spiders. We lie in the same heart fields with all birds and mammals.


Roll them, and thank amphibians.


Thank fish, too. These articulations made it possible to crawl out of the mud. Hours accumulate in the bowl / of the pelvis, three million/ years balanced / in bipedal performance. Your pelvic blades are short and wide yet fairly narrow, allowing you to balance all that torso, but the ilium opens like an ossified lily to birth big-headed babies.

Your legs

Enhanced pelvic fins.


Began as a cartilaginous rod called the notochord, and coelacanths carried them. When we moved to land as amniotes, then splintered into lizards, rabbits, pigeons, the column began to harden and articulate.


When you were a fish, you were neckless. You had to move your whole body to look left, look right. An ancient creature named Tiktaalik is the first known great grandmother to invent one. Necks, so handy for finding mates or prey. Necks can be so extreme. Of course, giraffes, who have the same number of cervical bones as you (seven), but did you know some plesiosaurs had seventy?


Another soft tissue, shy about leaving evidential traces. It does not stick to rock. Still, it seems we can trace everything back to fish, whose air bladders were repurposed for breathing air. In the transition, pre-ear, amphibians learned to hear with their lungs.


Had to be developed to hear airborne sound, and animals invented them in a few ways. Reptiles were the first to convert shark mandibles into inner ear ossicles.


What interests me most is how cephalopods invented a way to think along a completely different evolutionary line. Now they do it throughout their tentacles.


Seventy percent. That’s how much of it you share with a zebrafish.


The cover for Eleni Sikelianos' book of poetry, Your Kingdom

Bring this book home and read more about the wild roots of your past, present, and future.

Eleni Sikelianos is a poet and writer deeply engaged with ecopoetics, taking up urgent concerns of environmental precarity and ancestral lineages. Your Kingdom is her tenth book of poetry, alongside two speculative works of nonfiction-verse-image.