Scientists have identified a species of sea cucumber, dubbed a "real-life zombie" animal, whose severed tissue can survive and function independently for extended periods—potentially years—after detachment. This remarkable finding challenges conventional understanding of life and could have significant implications for human regenerative medicine.
The research, focusing on the scarlet sea cucumber (Psolus fabricii), observed that fragments of the animal's tissue, including tube feet, body parts, and tentacles, exhibited the ability to heal and maintain cellular function after being removed from the parent organism. Unlike other animals known for regeneration, such as lizards or starfish, detached tissue from these other species typically degrades within weeks or months.
A chance observation in the lab revealed that tube feet detached from a Psolus fabricii did not die but remained alive. This led researchers to conduct further experiments, placing various severed tissue fragments in flowing natural seawater teeming with microbes. Instead of breaking down, the tissue healed, with wounds closing and cells continuing to divide and reorganize.
These fragments demonstrated metabolic activity and immune function, indicating they were carrying out essential life processes. The tissue was observed to absorb amino acids directly from the surrounding seawater, effectively nourishing itself without a mouth. For over three years, the fragments continued to function as independent living tissue, showing no signs of aging or decay before the experiment was concluded to allow for publication of the findings.
This phenomenon suggests Psolus fabricii possesses unique biological properties that allow its detached tissue to persist independently. The study authors noted that this challenges the boundary between organismal life and cellular autonomy, prompting a re-evaluation of what it means for tissue to be alive.
The research team also experimented with tissue from sea stars and sea urchins, but those fragments decomposed quickly, highlighting the unusual capabilities of the scarlet sea cucumber. Future research will involve examining the DNA of the sea cucumber's surviving cells to determine if they exhibit signs of aging, which could confirm their potential immortality.