How Do Salamanders Regenerate Body Parts?
Salamanders have a superpower that sounds like it’s straight out of a movie: body part regeneration. When a salamander experiences the loss or amputation of a body part, they have the unique ability to regenerate it through a process called epimorphic regeneration.
Epimorphic regeneration does appear in other species such as deer (antler regeneration), zebrafish (fin/organ regeneration), and humans (we can regenerate the very tip of our fingers), but salamanders are one of the only species that can regenerate nearly all parts of their bodies, including complex structures such as their nervous system. How can they do this? To best understand epimorphic regeneration, take the example of a salamander’s tail being amputated.
Within a few hours after the injury, skin cells will cover the surface of the wound, acting as an initial protective barrier to keep the injury from getting infected. The rate of skin regeneration in salamanders is much faster than that of mammals, including humans—salamanders can create a new skin layer in as little as 10 hours, compared to 48-72 hours for mammals!
Next comes the cell proliferation and blastema cell phase. During this period, multiple blastemas gather at the site of injury. A blastema is a mass of cells with the ability to turn into an organ, limb, or even a missing salamander tail. The process of turning blastema into the tail is called morphogenesis, in which the movement of cells develops an overall image of what the final regrown tail should look like. The blastema will grow following this newly established shape, and individual cells will differentiate and take on their new specific cell types to grow the missing tail. The blastema will continue to increase in number due to cell proliferation (increase in cells due to growth and division), and slowly, the missing tail will regenerate.
The tail will continue to grow over time as more blastema reach the site of injury until it is fully regrown. This process can take anywhere from 40 days to a year depending on the age of the salamander, as regenerative abilities weaken with age. The success of regeneration will also change depending on the amount of times the same body part has regrown. Ultimately, whether it be a tail, limb, organ, heart, or something else, the salamander can regenerate it! (scar-free, too!)