National Geographic
Menu

Pictures: 5 Animals That Regrow Body Parts

When you were a kid you might have had the trauma-thrill of thinking you caught a lizard and opening your hand to find nothing but its squirming tail.

Some lizards and other animals can lose their body parts, but are masterful at regenerating them—a feat we humans are sadly less capable of doing (except in the case of our liver).

But what we are great at is learning from those masters. See below for a roundup of some of nature’s great regenerators and how they may help people down the road. (Related: “Will We Ever Regenerate Limbs?”)

Axolotl

You may recognize this face as the poster animal of this blog, but the Mexican axolotl hasn’t been spoiled by fame. This hard worker not only can make copies like Xerox—regenerating a missing limb; tail; and parts of their brain, heart, and lower jaw—but it’s a favorite study subject among scientists.

mexican axolotl picture

The Mexican axolotl. Photograph by Stephen Dalton, NHPA/Photoshot, National Geographic Stock

James Monaghan, a biologist at Boston’s Northeastern University, began studying axolotls during a grad school project and stuck with them since.

“If they’re paralyzed in the back they can recover the functions of their legs … They can make all new neurons and new connections that allow them to use their legs again, which is really one of the most incredible examples of recovery.”

His most recent research has focused on what genes regulate the axolotls’ regenerative abilities, testing what happens when certain genes are turned on or off. The axolotl “is a great model because it has a wide tool set to study regeneration,” he said.

Deer

If you read Thidwick, the Big-Hearted Moose as a child, you were amazed that an animal could just chuck and regrow those huge antlers on a regular basis. (See video: Deer and Antelope: Amazing Antlers.)

white-tailed deer picture

White-tailed deer can regrow their antlers. Photograph by Michael Fay, National Geographic Stock

Antlers growing back “is one of the most extreme examples of regeneration out there,” Monaghan said. A deer can regrow 60 pounds (27 kilograms) in as little as three months. (Also see: Deer Antler Velvet: What Is It and How Does It Work?)

“We’re finding that mammals have the ability to regenerate more than we appreciated before,” Monaghan said. Rabbits can regenerate parts of their ear lobes, bats can regenerate parts of their wings, and spiny mice can quickly regenerate skin and repair holes in their own ears, he noted.

So that’s why Minnie wears that bow instead of earrings…

Sea Squirt/Tunicate

This little squirt could be responsible for some big insight into regeneration.

The sea squirt, also called a tunicate, reproduces in two ways: Solitary types produce sexually, and colonial sea squirts can reproduce both sexually or asexually by budding off one another.

Otto Guedelhoefer, a researcher at University of California, Santa Barbara, said via email that asexual members of a colony share a circulatory system and are capable of whole body regeneration.

You would’t guess it to look at them, but sea squirts are also surprisingly similar to us genetically. An international team of scientists recently sequenced the genome of the tunicate Botryllus schlosseri and found that 77 percent of our genes were present, offering hope for regenerative medicines in people. (Also see “Sea Squirts Have Precursor to Human Heart.”)

For Guedelhoefer, a real area of intrigue is why tunicates’ regenerative abilities slow down with age, making them a potential platform for studying aging in animals—including us.

Starfish (Sea Star)

From Bikini Bottom to Fifth Avenue, everyone loves a starfish. These five-limbed creatures also have the ability to regenerate their arms and sometimes their whole bodies.

seastar picture

A Pacific blue sea star. Photograph by Creatas/PhotoLibrary/National Geographic Stock

Even if the critter is down to one arm, as long as it has its central nerve ring intact, it can grow into an entirely new starfish.

Er … sea star. The starfish, you see, isn’t actually a fish. It’s an echinoderm—cousin to the equally spiny sea urchin, sand dollar, and sea cucumber—so marine scientists are trying to get the name sea star to catch on as its new moniker.

It can regenerate. It can probably manage to rebrand.

Flatworm

It has been observed for centuries that if you cut a worm in half it will regenerate to become two worms. Biologist Thomas Hunt Morgan illustrated the regenerative powers of the planarian worm in a 1901 book but despaired of ever understanding regeneration.

How blown away he would have been by what’s available to scientists today.

“That’s what’s exciting,” Monaghan said. “We’re getting the molecular tools to ask what genes are regulating these regenerating phenomena.”

And planarians are still a star subject. In 2011, MIT researchers transplanted a special cell into a dying, irradiated planarian and the animal was able to fully regenerate. This year, researchers at the Max Planck Institute of Molecular Cell Biology and Genetics in Germany found a molecular switch in a flatworm that enabled it to grow a new head. Also this year, scientists at Tufts University showed that a decapitated planarian will not only regrow a new head, it will retain learned information as well as planarians who never lost their heads.

Guarantee: Next time you lose your keys, you’ll remember that a worm using a replacement head would probably have remembered where he/she put them.

Follow Liz Langley on Facebook and Twitter.

Comments

  1. Mr.Smily
    USA
    November 2, 2013, 3:32 pm

    the flat worms name is planarian

  2. Ngan Quach
    October 22, 2013, 10:08 am

    Love it! Weird and wonderful…:)

  3. Jessica
    phoenix
    September 22, 2013, 1:12 pm

    what sceince is used in this article

  4. Audelia Rodriguez
    Bakersfield California
    September 17, 2013, 6:48 pm

    Asombrada,en mi vida vida nunca habia visto un axolote. No hay duda,la naturaleza es maravillosa.

  5. 黄斌
    China
    September 9, 2013, 12:41 pm

    Amazing world

  6. Elysia
    USA
    September 9, 2013, 11:36 am

    Seriously cool.
    I’ve never been disappointed in the attempt to catch a lizard, but I was traumatized as a child when a worm, which I had been carrying on my finger to feed to the fish in my backyard pond, separated and became two. At the time, I didn’t understand that both halves were still alive and well. I figured it was either dead or in indescribable pain.

  7. Frank Smit
    Groningen, The Netherlands
    September 9, 2013, 12:39 am

    Liz do you have a theory why it is mostly sea animals that are able to regrow? Or is that a faulty assumption from my part?

  8. kw Jung
    s. korea
    September 7, 2013, 9:07 pm

    human being regenerate their nail, hair, beard.
    I didn’t see liver could be regenerated. ^^

  9. Rev Dean Greer, D.Min.
    San Francisco, CA.
    September 7, 2013, 7:32 pm

    Eye has not sees, nor ear heard, and neither has it entered the heart of man the glory that God has prepared for them who love Him, (Rom. 8:18-19)
    We do not currently have the capacity to comprehend the creative glory of God’s amazing creation!

  10. Liz Langley
    September 7, 2013, 5:29 pm

    @Ahamed They sure can. I mentioned up top how little kids try to catch lizards and open their hands to find only the tail. That kid was me! :) I was horrified! But I learned that lizards were even cooler than I thought.

  11. Jeremiah
    Rajahmundry
    September 7, 2013, 1:48 pm

    Nice & rare pictures

  12. amr mlege
    September 7, 2013, 4:14 am

    Wonderful and very beautiful I love nature

  13. Viviana
    Argentina
    September 6, 2013, 11:42 pm

    Maravilloso, La naturaleza no dejará nunca de asombrarme. Gracias! Y gracias a Dios por tantas hermosuras!

  14. shonee roque
    Philipines
    September 6, 2013, 10:27 pm

    Simple earthworm can regenarate its chopped body, because it has heart all over its body.

  15. Dolland Kelly
    Ghana,
    September 6, 2013, 9:14 pm

    this is what in spider man,the doctor wanted to also do.hoping to regrow his arm. God’s creation is so beautiful.never knew something od this sort exist.

  16. RAMY
    Home in Alexandria - Egypt state
    September 6, 2013, 9:05 pm

    Wonderful professional imaging and the ability to uncover the secrets of the ocean floor and the power and excellence for National Geographic International

  17. stella
    armadle
    September 6, 2013, 7:54 pm

    cool but not true

  18. elisabeth
    amsterdam
    September 6, 2013, 3:57 pm

    …that pixie powder doesnt work..

  19. Steven Rafter
    Melbourne
    September 6, 2013, 1:19 pm

    Funnily enough – humans are not too bad at it either – we replace skin and hair constantly… it’s the organs, limbs and neurons that we gotta work on…

  20. Dave
    Halifax Nova Scotia Canada
    September 6, 2013, 12:42 pm

    Nature continues to amaze us with new to us species. And we also continue to destroy an existing to us species everyday!

  21. Ahamed
    Chennai. India
    September 4, 2013, 2:37 am

    What about lizard. It can regrow it’s tail.

  22. Bill Parkes
    UK
    September 3, 2013, 10:59 am

    Nature is not just wonderful but amazing as well

  23. Brian
    United States
    August 30, 2013, 8:00 pm

    Many stories of powdered pig bladder being applied to recently lost human finger tips that then grow back, finger nail and all. Lately, it is being used on wounded Veterans on other areas of the body with promising results.

  24. Liz Langley
    August 30, 2013, 3:11 pm

    I mean conch can regrow their eyes…I’ve never heard of octopi doing that. :)

  25. Liz Langley
    August 30, 2013, 3:10 pm

    @Mouthemoucubou They do, indeed! I only focused on a few here, but there are other animals that regenerate parts, including octopi and conch….they can regrow their eyes!

  26. Liz Langley
    August 30, 2013, 1:33 pm

    @Iyana, if you click the link that says “Related: Will We Ever Regrow Limbs?” that leads to a NatGeo column by Ed Yong with more detail about how animals regenerate limbs. It’s fascinating stuff, hope it helps you with your research!

  27. Mouthemoucubou
    Hatboro,PA
    August 30, 2013, 12:44 pm

    What about octopuses? They can regrow tentacles!

  28. Weward hurlston
    Cayman Islands
    August 29, 2013, 8:16 pm

    Beautiful, marvelous, revealing God’s handy work in nature.

    Thank you.

  29. Brenda Kim
    s. korea
    August 29, 2013, 3:05 am

    wow, not just reputails, huh? ~
    amazing.

    Among them, the blue sea star is so beautiful ~

  30. lyana
    August 28, 2013, 6:34 pm

    I really enjoyed this article. im using it as my current science article to answer some questions on it. THANKS!