Detailed guides to painful problems, treatments & more

Salamander and Regeneration Science

Why does have a salamander mascot? Their regenerative superpower is an inspiring, profound example of what is possible in biology and healing

Paul Ingraham • 10m read

Until man duplicates a blade of grass, nature can laugh at his so-called scientific knowledge.

Thomas Edison

Salamanders are a biological marvel: they are the only larger vertebrates that can regenerate entire limbs, a capacity for healing unmatched in the animal kingdom. Lizards can grow new tails, and human children can regrow the tips of their fingers, but only the salamander can cook up perfect shoulders, elbows, wrists and hands from scratch. (For bonus points, they are also photosynthetic — no, seriously.1)

And it’s a perfect mystery how they do it. If we only understood how their cells do this wonderful thing, what else would we know about biology and healing? How would it change health care? Our ignorance and our potential are dizzying.

And yet progress has been made. In 2010, researchers were able to trigger impressive regrowth of joint surfaces in rabbits.2 We’ve also found a mammalian gene that suppresses regenerative function. When the gene is turned off, presto: animals that couldn’t regenerate suddenly can!3

Forget jetpacks: I want the future to bring us regeneration powers! I could use at least three regenerated body parts: an acromioclavicular joint that got ripped up a decade ago and has given me hassles ever since, a cervical intervertebral joint that’s menacing my spinal cord a bit, and flaming Achilles tendons that have been through so many bouts of tendinitis now that it’s frankly amazing neither of them has ruptured. And I’m not even 50 yet!

The salamander’s talent is an ideal example of and symbol for healing, and for what health care professionals do — for how much there is to learn, and for learning itself, the regeneration of our minds if not our limbs!

Regeneration powers, anyone?

It’s pretty pie in the sky still, but the genetic potential actually exists to heal almost magically from massive injuries — just like the comic book character, Wolverine … & salamanders.

Cells as medicine: the use of regenerative medicine for injuries and chronic pain

When I first started writing about musculoskeletal and pain medicine in the early 2000s, I never expected my interest in salamanders and regenerative medicine to be anything more than symbolically relevant — just a quirky source of inspiration.

But there are now three major types of regenerative therapies being widely used to help the kinds of patients I write for.

Stem cells are generic cells that do not yet have a job. In theory, they can become what we need them to be, which is a potentially powerful tool in medicine. Stem cell therapy is a broad concept in regenerative medicine, and it is a hot hot hot topic right now. Stem cell therapy is being used (controversially) to treat injuries. Not necessarily effectively, but it is being used.

Stem cell therapy is identical in spirit to the other two main regenerative therapies in musculoskeletal and pain medicine: platelet-rich plasma and autologous chondrocyte implantation. They use mature, specialized cells, so they are just cell therapies. But regeneration is the goal of all of these methods.

All three therapies are practically the same thing with regards to safety, efficacy, and the concerns of skeptical consumers and regulators. They are biologically intriguing treatments that might amount to something someday — after all, we know regeneration is possible, thanks to salamanders! — but it’s a depressing mess so far, instead of being inspiring and promising. These treatments are all being rushed to market in the same way, all sold as high-tech medicine to desperate consumers long before the science is done.

Wounds that do not heal

Most of the time it’s hard not to heal. You couldn’t stop it if you tried. The body is going to bounce back from most kinds of injuries, almost no matter what — it’s just a matter of time, with or without tricks like icing or soaking in an Epsom salts bath. It’s infamously impossible to rush healing.

Or is it?

But stubborn pain problems, the subject of this website, are different by definition. Or healing itself fails, or pain persists even when the tissues seem to be fine (like common muscle aches), or a bit of both. Repetitive strain injuries, which usually afflict connective tissues like the it band, plantar fascia, or the wrapping around your shin bones, are slow-motion traumas that often seem immune to recovery — this is what makes them both terrible and fascinating. They usually don’t heal because they need more rest than most people will give them, but sometimes healing just doesn’t work. Sometimes bone fractures and lesions will not close (a problem every surgeon dreads). Sometimes pain persists because of a known glitch in biology!

The regenerative healing powers of the salamander are amazing and bizarre … but they are also darkly reflected in the human wounds that do not heal. It doesn’t seem fair: salamanders can regenerate entire limbs, but we often can’t recover from a little overuse!

This is the “salamander” that lives on my desk. Got this li’l guy many years ago in Playa del Carmen. Technically a gecko, not a salamander—heresy! But he is so blue (and fun) that I decided he was close enough to the salamander for mascot duty.

Other kinds of critter regeneration

The African spiny mouse

The only mammal with some impressive regenerative powers.

Many tiny organisms are masters of regeneration. But it’s rare in animals larger than a speck, and particularly rare in mammals. If regeneration is possible in any mammal, then there’s hope for us.

And it is possible. This neat 2012 science story is promising: “Biologist discovers mammal with salamander-like regenerative abilities.”4 The African spiny mouse does a far better job at regenerating any part of itself than any other known mammal to date. Salamanders are much better at regeneration, in every way, but at least we know mammals aren’t completely left out of the regeneration game.

And there are many other examples of limited critter regeneration of specific body tissues and parts.

The mole rat’s superpower

This isn’t about salamanders or regeneration, but I think I’m going to start turning this page into a general collection of cool biology of pain and healing throughout the animal kingdom.

“To deal with their miserable lives” naked mole rats evolved to feel no pain:

And yet in this harsh environment, under extremely crowded conditions, the naked mole rat has evolved to be virtually indestructible: these small mammals almost never get cancer, live to be over 30 (much longer than other rat species), and they are insensitive to acid burns. A study in Cell Reports reveals one secret behind these rats’ abilities. Evolutionary tweaks to the amino acids in their pain receptors make naked mole rats extremely insensitive to pain after they are born.

I think it’s surprising and fascinating that immunity to pain isn’t a more common adaptation in biology. Clearly pain has potent survival benefits — the ultimate double-edged sword.

This salamander is skeptical

The salamander is more of a mascot than a logo. He’s a character. He has represented this website with a bit of flair since the very beginning (since before it was even called PainScience6).

The salamander does not believe everything he hears. The salamander is no sucker. The salamander watches MythBusters, and applies the same attitude here: let’s just check that. Sometimes the salamander squints at stupid ideas in health care and says, “Meh, not even worth testing.”

When something seems too good to be true, the salamander rolls his beady little eyes, heaves a sigh, and gets ready to do brain battle with the forces of the evil Lord Gullible. The salamander is especially irritated by big promises. He is just not that impressed by a lot of expensive therapies and products, like acupuncture, Traumeel, or platelet-rich plasma injection (a therapy that actually claims to regenerate tissue).

The salamander is living, breathing proof that there are miracles enough in biology without inventing new ones.

Sometimes you just need to hear sense from a salamander.

Fine, dash my hopes with all your crazy logic and science. Be that way.

funny reader


What’s new in this article?

2019 — New section, “Cells as medicine: the use of regenerative medicine for injuries and chronic pain.”

2016 — New section about the naked mole rat’s pain immunity superpower.

2000 — Publication.


  1. Kerney R, Kim E, Hangarter RP, et al. Intracellular invasion of green algae in a salamander host. Proceedings of the National Academy of Sciences. 2011. PainSci Bibliography 53091 ❐

    It’s not enough that salamanders have seemingly miraculous regenerative powers, without equal in vertebrates. Oh no, salamanders have to be more amazing still, by being the only vertebrates that are effectively photosynthetic, thanks to a deep symbiotic relationship with an algae, a proper endosymbiote. That is, the algae don’t just hang out around the salamander cells, but actually in them — and you can even see the algae, the only endosymbiote visible to the naked eye (you can see it in their eggs). Incredible.

    Just how special are you, salamanders?!

  2. Lee CH, Cook JL, Mendelson A, et al. Regeneration of the articular surface of the rabbit synovial joint by cell homing: a proof of concept study. Lancet. 2010 Aug;376(9739):440–8. PubMed 20692530 ❐ PainSci Bibliography 54932 ❐

    Build it and the cells will come. This proof-of-concept study demonstrated what happens if you replace the end of a rabbit’s femur with an empty plastic “scaffolding” of exactly the same shape, and then fertilize it with transforming growth factor beta3. Cells migrate into the framework and start building bone and cartilage! “The entire articular surface of the synovial joint can regenerate without cell transplantation.” Without the growth factor, not much happened: much less than half as many cells moved into the new habitat.

    These findings suggest that “regeneration of complex tissues is probable by homing of endogenous cells.”

  3. [Internet]. Humans Could Regenerate Tissue Like Newts By Switching Off a Single Gene; 2010 Mar 16 [cited 15 Aug 5]. PainSci Bibliography 55649 ❐
  4. Seifert AW, Kiama SG, Seifert MG, et al. Skin shedding and tissue regeneration in African spiny mice (Acomys). Nature. 2012 Sep;489(7417):561–5. PubMed 23018966 ❐ PainSci Bibliography 54267 ❐
  5. Citation needed and harder to find than I hoped, but entomologist Gavin Pitts talks it up around the 5:00 mark in the Caustic Soda episode “Web Building Spiders.”
  6. was “” for more than a decade, but I never really liked it. I was always uneasy with the connotations of “save”: it smacked of a healing promise I can’t keep, and like Jesus might be involved somehow. I moved everything to in late 2014. For more information, see Why Became All about the 2014 change from to


linking guide

2,200 words