As I said last time, Natural History is a subject that is very interesting to me and, as a result, I am reluctant to get off it. So you can expect a few more Natural History columns from me here in the OnLion’s Pride as it is now named (and yes I’m quite proud of myself for coming up with that name). The fact is, there are so many fascinating things going on around us that we’re unaware of. People often absorb themselves in the worlds of fantasy and science fiction but really they need look no further than their own world to find things that are infinitely more incredible, and are often the inspiration for these fantasies in the first place.

This brings me onto the subject of this column which is something truly unbelievable. If I was to ask you to name an immortal being, you would probably think of creatures from fiction or folklore such as vampires or zombies; creatures that have risen from the dead. It is highly unlikely that you would think of a very small species of jellyfish named Turritopsis nutricula but if you did then you would be absolutely correct. T. nutricula are very small, around 4.5mm in both length and diameter, and bell-shaped. Perhaps my example of zombies and vampires earlier was a little misleading, T. nutricula are by no means “undead” but are in fact something far more exciting. In its jellyfish form, the species is able to revert back to its polyp stage once it has reached sexual maturity. Once it has reverted to a group of polyps these polyps can then grow once again to be sexually mature, in effect this makes the species biologically immortal.

T. nutricula have never been monitored in such a way as to prove their immortality (as you can imagine this would be quite a difficult study to perform). However, they do have the potential to be immortal as they are the only species able to alter their cells from a sexually mature state to form polyps again. They do this by a process called transdifferentiation which is very rare, and mostly occurs only in very specific areas. For example, if the lens of a salamander’s eye is removed, iris cells will transdifferentiate to form cells that make up a new lens.

There are few other species that can be truly considered immortal. It is sometimes said that bacterial colonies are immortal due to the way in which they reproduce exponentially through cell division. There is also one other species which is speculated to be immortal, bristlecone pines, the oldest living example of which is nearly 5000 years old causing some to theorise  that the species is immortal but perhaps that is a subject for another column.

So there we have it, there may be examples of immortality living in our world. The exciting thing about T. nutricula is that, although they are thought to have originated in the Caribbean, they have now spread to all over the world, though I think you would struggle to find them. Rather worryingly however, their immortal nature has caused some scientists to speculate that they will continue to spread indefinitely, we may be looking at a worldwide invasion, and one that will go one forever.

 Augustus, 6.1