Like the ocean, it seems that many bodies of freshwater are dark and full of terrors. For example hydra, an invertebrate freshwater creature that measures less than an inch long, is bizarre with the ability to regrow its severed head and body parts. In the video below, PBS shows off some hydras performing their characteristic regrowth trick. Which is somehow just as magical as it is creepy.
BoingBoing picked up on the above video, which PBS recently posted to YouTube as a part of its
Hydra, which earns its name from the eponymous ancient Greek serpent monster, is actually an entire genus of organism; one that consists of minute individuals that can heal themselves back to full health. The body of each hydra consists of a thin, often translucent column of cells with a closed lower end. At its top end, the hydra has an opening that both ingests food and ejects waste. Around this dual-use opening is a circlet of anywhere from four to 25 tentacles.
The hydra is able to achieve “biological immortality” thanks to its abundance of stem cells; that is, generic cells from which all other cells with specialized functions are generated. When one of the hydra’s tentacles is cut from its body, for example, its stem cells transform into the type needed to perform the tentacle’s function. The hydra is even able to recover if somebody splits it in two; using the stem cells to regrow two new, whole bodies.
Scientists are studying the hydra as it may ultimately lead to better anti-aging treatments. While adult humans each have a tiny number of stem cells in their bodies, the generic, life building blocks make up half this organism’s body. And if scientists can glean how the hydra avoids aging using those cells, the same process may apply to people; even to regrow their limbs. Which is so profound it seems tempting to…