Wildlife TV

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Is Immortality Real?

on September 22, 2014

Immortality has been a subject that has fascinated human beings for the longest time. Many legends and mythologies discuss the possibility of supernatural beings and creatures with everlasting life and tell tales of heroes and adventurers seeking the fountain of youth or the elixir of life. In reality, humans are forced to be content with what little time we have on this Earth but left wondering; is immortality possible?

Ageing and eventually dying are natural processes that are a part of the rules of life, however, there are a few organisms that are capable of bending or even breaking these rules.

The animal kingdom is richly diverse and, as you might expect, different animals have vastly different lifespans and many have very brief lives, for example, the worm-like gastrotrich only has a few precious days of life in which to do all of its eating, fighting and mating.

 

Gastrotrich

A gastrotrich is a tiny worm-like aquatic creature that has one of the shortest lifespans in the natural world, only a few days. Photo Credits.

On the other end of the scale are animals that are extremely long-lived. An Aldabra giant tortoise (Aldabrachelys gigantea) that died in a zoo in India in 2006 was believed to have been born in around 1750 making him over 250 years old! The oldest mammals are believed to be bow-head whales (Balaena mysticetus); one individual caught in 2007 was found to have a 19th century harpoon embedded in its neck!

These remarkable cases might make our human lifespans seem measly by comparison, however, there are some organisms who live on a time-scale far beyond what we could ever experience. Some species of Antarctic glass sponges, hexactinellids, could live for as long as 15,000 years! Imagine a life longer than the whole history of human civilization.

 

Antarctic Hexactinellid Glass Sponges

Hexactinellids are glass sponges found in Antarctic waters. They are actually animals and may live for as long as 15,000 years! Photo Credits.

Longevity is impressive, but it is quite different from immortality. As unbelievable as it may seem, however, there are organisms that may be able to live forever.

Lobsters (family: Nephropidae) are animals that we are quite familiar with (mainly as an expensive meal), but they have some fascinating characteristics, most notably; they do not age. Lobsters grow continually throughout their lives but they do not get weaker or lose any function as they go, indeed, it has also been suggested that they become more and more fertile as they grow. A giant lobster (named George) was caught off the coast of Newfoundland in 2008 and was believed to have been approximately 140 years old! It is theorised that if left alone, lobsters might have the potential for immortality, growing indefinitely until they are killed by an external force such as a predator or disease. Lobsters achieve their longevity thanks to enzymes that repair damage to their DNA.

 

Lobster

Lobsters are a family of marine crustaceans. They grow continually throughout their lives but do not age. Photo Credits.

Turritopsis dohrnii is a species of tiny jellyfish that has a unique lifestyle that potentially qualifies it as immortal. These creatures live their lives up until a certain point, when conditions are right, when they will regress back to their infant form, a polyp. Almost like Benjamin Button, they age in reverse but they can repeat this cycle many times, potentially forever. Each time they revert to their immature stage, they are also capable of budding and producing whole new colonies of individuals.

So it seems as if some creatures have unlocked the secrets of immortality, however, immortality is quite different from invincibility. The process of ageing is also called senescence; this is where cells and organs deteriorate over time, whether as a result of being exposed to the stresses of everyday living, or the gradually increasing ineffectiveness of DNA replication. However, organisms that have beaten senescence are not guaranteed never ending life, there are my threats to their existence such as disease, fatal injury, predation etc. For example, the ‘Benjamin Button jellyfish’ rarely gets to even complete one of its life cycles in the wild because it is usually eaten by something first!

There are creatures that also attempt invincibility too: Tardigrades (sometimes called by the cuter names water bears or moss pigs) are microscopic animals that have a remarkable ability to survive extreme conditions; they earn the title of ‘extremophile‘. It seems to be very hard to kill a tardigrade; they can survive extreme sub-zero temperatures as easily as boiling water, they can survive the extreme pressures of the deep ocean as easily as the vacuum of space, they can survive without any food or water for years on end and can even tolerate extremely strong radiation. They can be found almost everywhere on Earth and have lived happily for tens of millions of years. Individual tardigrades can live for several decades depending on environmental conditions; not immortal but pretty close to indestructible!

 

A Tardigrade, or Water Bear

Tardigrades, or Water Bears, are microscopic animals that can survive almost any extreme condition. Photo Credits.

Humans have accomplished many great things, but sometimes we are reminded how fragile we are as animals. The natural world is full of amazing creatures with abilities that can humble us. Perhaps there are things we can learn from them and someday have a chance at immortality ourselves!

Thanks for reading!

Much love,

-Nick

 

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