## Quick Facts - The earliest known observations of [liver regeneration](https://reddit.com/r/AskHistorians/comments/qratux/is_the_story_of_prometheus_indication_that/hk64r68) occurred in the 1880s. The phenomenon was confirmed (in rats) in the 1930s. - The forest on the floodplain of Kenya's Tana River appears to be slowly dying. It can't regenerate because the [upstream dams have stopped the floods](https://archive.internationalrivers.org/hydrological-effects-of-dams) the region relies on. - It takes female golden orb spiders about a week to [regenerate their silk](https://www.wired.com/2009/09/spider-silk/) after it's been harvested. - Scientists have invented a "self-assembling gel" that [triggers nerve regeneration](https://www.newscientist.com/article/2297272-paralysed-mice-walk-again-after-gel-is-injected-into-spinal-cord/) in mice and can help cure paralysis. - Three-banded panther worms are about the size of a Tic Tac and can [regrow any part of its body](https://neurosciencenews.com/regeneration-transgenic-worms-19612/) if you cut it off. ## Endless Arms Some scholars think that octopuses ([octopodes? octopi?](https://www.merriam-webster.com/words-at-play/the-many-plurals-of-octopus-octopi-octopuses-octopodes)) are the source of hydra myths. Imagine an octopus or a squid, then flip it on its side. Now imagine the big bulbous head is actually its body. Now imagine its arms — which can regenerate — are actually long necks. Compare that mental image to [this visual](https://www.smithsonianmag.com/science-nature/five-real-sea-monsters-brought-life-early-naturalists-180953155/). Pretty wild, huh? ## Complex Cells Though salamanders are significantly larger and more complex than worms, they can also regenerate almost anything — including their spinal cords and eyes. The axolotl has the largest genome ever fully sequenced, and has about [ten times the base pairs of human DNA](https://www.smithsonianmag.com/science-nature/complete-axolotl-genome-could-reveal-secret-regenerating-tissues-180971335/). Scientists are still trying to figure out how they make the cells near the site of an injury revert to stem cells and [help us live forever](https://astralcodexten.substack.com/p/book-review-lifespan). ## Eating Liver The Prometheus myth, in which a god is has his liver eaten every day as punishment for giving the gift of fire to humans, is a popular myth involving regeneration. It's probably just a coincidence, though: the ancient Greeks who told stories about Prometheus almost certainly didn't know about the liver's regenerative powers. Here's a really [detailed explanation of how we know that](https://kiwihellenist.blogspot.com/2020/11/prometheus.html). ## Hollow Tails When certain species of lizard are threatened, they can drop their tails to evade predators, then grow a new one over a few weeks or months. In most cases, the new tail is supported by cartilage, instead of bones and nerves. Scientists figured out how to [implant gene-edited neural stem cells into adult lizards](https://newatlas.com/biology/crispr-stem-cell-therapy-lizards-regeneration) to get them to regrow "perfect" new tails. --- 📗 [ICYMI](https://www.merriam-webster.com/words-at-play/what-is-icymi): If you found this interesting, you may also enjoy my investigation into whether it would work for a fantasy culture to [herd giant vegetarian spiders for their silk](https://eleanorkonik.com/spidersilk/) %% ( [[2020-12-28 Spidersilk (DRAFT)]] ) %%.   💚 If you learned something from this overview, consider forwarding it to a friend and encouraging them to [sign up](https://eleanorkonik.com/membership/) for more research deep dives into obscure history and science. 🧳 I'm headed to [The 79th World Science Fiction Convention](https://discon3.org/) in Washington D.C. this week, so if you're planning to be there (or happen to live near Dupont Circle), let me know if you want to say hi in person!