First of all, let’s talk about regeneration and how some animals can do it. Regeneration is a natural process that allows plants and animals to replace or restore damaged or missing cells, tissues, organs, and even entire body parts to full function.
As a kid, we all have had the trauma of seeing a lizard detaching its tail from its body when we try to catch it. The lizard escapes and all that is left is the wiggling tail in front of us. But the lizard can grow its tail through Regeneration.
Regeneration occurs widely in the animal kingdom, although their regenerative capacity varies. Invertebrates can regenerate their entire organs. Some vertebrates, such as amphibians and fish, are capable of regenerating substantial parts of their body but not an entire organism.
Urodele amphibians have the capability to regenerate a wide array of tissues and organs, including limbs, tails, jaws, spinal cords, and lenses, and hearts.
So how come these animals’ powers of regeneration are so good? In short, the Stem cells. Stem cells are undifferentiated cells that have the ability to grow into any type of cell or tissue. All animals have these.
The limb regeneration process is basically the cells dedifferentiate and form a mass called a Blastema. And from this structure, the cells differentiate again and can regrow an arm or a leg. This whole process can take anywhere from a month to three months depending on how old the animal is.
Here are the top 10 animals that can regrow their body parts.
1. Mexican Tetra
Researchers in Mexico are studying cave-dwelling tetra fish to better understand why some animals can regenerate tissue but others can’t. The scientists removed some of the heart of river fish and cavefish from the species Astyanax mexicanus. They found that the river-dwellers tetra fish are capable of self-healing their heart tissue and cave-dwellers cannot do the same, the cavefish just grew scars over the damage.
2. Starfish (Sea Star)
These creatures can regrow arms that detach from their central disc, and in some species has been observed that they even can regrow an entire body from a lost arm. To do this the starfish will store nutrients in the arm until it is able to regrow its mouth. Both cases are true for the Starfish that lose arms can grow new ones, sometimes an entire animal can grow from a single lost arm.
3. African Spiny Mouse
The African Spiny Mouse is able to release its skin tissue when attacked, and then completely repair it. To date, spiny mice are the only mammals known to do so. It also has the ability to heal holes in its ears. the spiny mouse quickly closes holes with new skin. It can also regenerate hairs, sweat glands, fur, fat cells, and cartilage, with little or no scarring. Like salamanders and lizards, when a tail is lost, these mice can also grow a new one.
When it comes to mammals, deer antlers are the only organ that can fully regenerate. These animals could regrow their huge antlers on a regular basis. A deer can regrow 60 pounds (27 kilograms) of its antlers in as little as three months. At first, the antlers are small spikes that they shed like baby teeth and then they grow a larger, more branch-like rack of antlers by the time they are three years old. Deer will continue to grow, lose, and regrow larger antlers throughout their lives.
5. Sea Cucumber
Sea cucumbers have bodies that can grow to be three feet long. If cut into pieces, each one can become a new sea cucumber. This marine animal has a remarkable ability to regrow its organs in short periods of time, regrowing damaged parts and healing deep wounds in as little as a week. When threatened, some sea cucumbers can mutilate their own bodies as a defense mechanism. They contract their muscles and throw some of their internal organs out of their anus. The missing body parts are quickly regenerated.