13 Animals That Can Regenerate Body Parts

I have a pet axolotl, and I love telling people about how axolotls and other salamanders are capable of regenerating body parts. It’s crazy how a small, fragile creature can regrow limbs and even organs when needed. As I was doing more research about these fascinating abilities, I realized that salamanders aren’t the only animals with regeneration abilities.

There are lots of animals that can regenerate body parts. Some can only regrow certain things while others are capable of extreme regeneration.

What Animals Can Regenerate Limbs?

Regeneration is a behavior that’s present in a wide range of animal species. It’s most common in aquatic animals, especially invertebrates, but there are a few amphibians, reptiles, and even mammals that have these capabilities too.

Animals that can regenerate have unique cells that allow them to do so, which is something that humans lack. It’s important to note that regeneration is different than repair. Some animals can repair damaged body parts, but that doesn’t mean they can regrow missing limbs. As animals get older, it’s harder for them to repair and regenerate.

How Do Animals Regenerate?

Every animal’s body works a little differently, but in general, regeneration is possible because of stem cells, which are cells capable of developing into many different cells. When studying an amputated salamander leg, scientists found that stem cells were attracted to the wound, creating a mass of tissue called blastema. That mass gradually grew into a new leg.

Animals That Can Regenerate Body Parts

Animal regeneration is fascinating and varies from species to species. Let’s take a look at some of the incredible animals that can regenerate, along with what specific parts they can regrow.

1. Salamanders

I’ve been obsessed with salamanders ever since I was a kid. The first time I learned about their impressive regrowing abilities, it seemed too insane to be real. Yet, it’s true that salamanders can regrow almost any body part, including tissue, limbs, spinal cords, hearts, and other organs. Axolotls have the same regeneration abilities since they’re a type of salamander. Salamanders have delicate bodies, so this ability helps them survive.

2. Lizards

Lizards might look like salamanders, but they’re very different (they’re reptiles instead of amphibians). They cannot regrow as many body parts as salamanders, but they can famously drop and regrow their tails. Not all lizards can do this, but many of them can, such as skinks, geckos, and anoles. 

Many lizards can only do this once, and their tail may not grow back the same as before. In some cases, several tails can grow from the same spot when regenerating. Thus, lizards usually only drop their tails if they need to quickly escape a predator.

3. Starfish

Starfish are one of the most impressive animals when it comes to regeneration. They can regrow most body parts and neurons. Some starfish can even regrow an entire new body from one arm. The extent of the regeneration ability depends on the type of starfish, how much of the body is left, and how much damage there is.

4. Sea Cucumbers

Sea cucumbers are another aquatic invertebrate with extensive regeneration capabilities. They can regenerate their body wall, nervous system, and internal organs. This includes entire digestive systems and reproductive organs. In fact, sea cucumbers can even eject some of their internal organs as a defensive mechanism, which they eventually grow back.

5. Zebrafish

Not all fish can regenerate, but zebrafish are unique. These tiny striped fish can regrow all types of body parts, including their heart, brain, fins, kidneys, spine, retinas, and pancreas. Surprisingly, zebrafish have the same major organs and tissue as humans, so scientists are researching their abilities to hopefully find a way for humans to regenerate body parts one day.

6. Mexican Tetras

Mexican tetras stand out from other tetra species because they’re blind, pale, and live in caves. Thus, they have unique features that other small fish don’t. Surface-dwelling Mexican tetras able to regenerate heart tissue without any scarring. The ones living deep in caves don’t seem to have the same ability because they evolved differently. The gene lrrc10 seems to be responsible for the regeneration properties.

7. Deer

Mammals may not regenerate legs or organs like other types of animals, but deer can regenerate their massive antlers. Every year, deer lose their antlers in the winter due to lowered testosterone and a change in the environment. Yet, those antlers grow back good as new when the weather warms up again. Hormonal changes lead to this process.

8. Shark

While we lose our baby teeth to make room for our adult teeth, there’s nothing to replace our adult teeth if they fall out. Sharks don’t have that problem because they have an endless supply of teeth. When sharks lose one of their razor-sharp teeth, the cells in their bodies start working hard to grow a new tooth. Sharks typically lose about 30,000 teeth in their lifetime!

9. Conch

Most people think of conches as pretty shells, but a sea snail lives inside the shell. They have their hard shells to protect them, but they’re very sensitive if they peek out. Luckily, they can regrow their eyes if a predator attacks them. In many cases, it only takes a few weeks for a conch’s eye to regrow.

10. Crayfish

Crayfish can regrow lost legs and limbs. However, the process isn’t as speedy as other animals that can regenerate. Their limb grows back little by little each time they molt, so the process can take several months and sometimes even a whole year. Since most crayfish only live two to four years, that’s a long time to go without a body part.

11. Jellyfish

Jellyfish have speedy regeneration abilities. They can regenerate lost tentacles in only a few days. They can also regrow organs and entire bodies from only a body fragment. Immortal jellyfishes take this to a whole new level because they can revert back to earlier life stages, allowing them to potentially live forever.

12. Octopus

Octopuses can regrow tentacles, parts of their eyes, and even their nervous system. Whenever an octopus loses an arm, the body quickly gets to work regrowing a new one. The new arm looks identical to the original, including the flexible suckers and inner nerves. Other cephalopods, such as cuttlefish, also have this special ability. 

13. Planaria

Planaria are a type of aquatic flatworm known for their amazing regrowth abilities. They can regenerate nearly any body part, including heads, tails, and sides. They can even regrow entire bodies from one fragment. Depending on the damage, the process can take a few days to a few weeks. They have large amounts of pluripotent stem cells to help with the process.

While not the same species, other worms, like earthworms, can heal rapidly from injuries and even regrow missing body parts.

Frequently Asked Questions

What Animal Can Regenerate the Fastest?

Jellyfish have extremely fast regeneration times. They can regrow a tentacle in only a few days.

Can Any Mammals Regenerate?

While mammals cannot regenerate limbs and organs, deer can regenerate antlers. Mammals have different biological structures than other types of animals, so they don’t have the same abilities.

Why Can’t Humans Regenerate Body Parts?

Humans don’t have the same cells and body structures as animals that can regenerate. When we get injured, our bodies form scar tissue, which prevents that part from growing back. Scientists are researching regeneration in animals to hopefully discover a way for humans to regenerate in the future.

There are Lots of Animals That Can Regenerate!

Animal regeneration is a fascinating concept. A wide variety of animals can grow back limbs and even organs that they’ve lost, which seems like something that would happen in a fantasy novel rather than real life. I love learning about the unique abilities of animals, and I hope discoveries like this will help scientists learn how to make life better for animals and humans.