With
Batman and Superman preparing to do battle in our movie theatres[1],
perhaps you have wondered, "What is the most invulnerable creature on our
planet?" The armadillo? The Blue Whale? Lions? Elephants? No, there is one
creature that is much more durable than all of these. It can survive being
boiled and frozen; in fact it can live in temperature ranges of −272 °C to
149 °C. It can tolerate the vacuum of space while being exposed to more
ionizing radiation than any other creature. It can also survive without food or
water for decades (some have been rehydrated after 120 years of desiccation).[2]
No, it is not that fictional life form from the Alien[3]
movies. Truth is sometimes stranger than our fictional screenplays.
The
Tardigrade, or Water Bear, pictured here, wins the gold medal for invincibility. However,
you would need a very small ribbon to hang the award around its neck; Water
Bears are only visible with a microscope and measure approximately 1.5 mm
across their longest dimension. They are certainly weird looking animals and
would likely scare the wits out of any of us if they were more like half a
meter in length. Fortunately, unless you go looking for them, you will never see one. They like to live on mossy surfaces where they thrive on microscopic drops of secreted
liquid. They can also live in our water supply, the gutters of our city streets,
and our cupboards.
Researchers (and yes there are those who study these tiny animals in the wild) have recently
made a remarkable discovery about Tardigrades. They have the ability to
scavenge and incorporate DNA from other living creatures. (Note well, the paper related to this research has been subsequently questioned and researchers are working to confirm or deny the results of this research.) In one recent study,
it was found that "the Hypsibius dujardini
tardigrade incorporated into their own DNA genes from more than 1,300 bacterial
species, 40 archaea, 91 species of fungus, 45 plant species and six viruses."[4]
When severely dehydrated, Water Bears, and other organisms around them, spill
out DNA from broken cells. The unique thing about the Tardigrade is that when
water returns to the environment, they can quickly sew their DNA back together
and sometimes incorporate other free-floating DNA. It is likely this feature
that has made them so invulnerable to extreme conditions. Move over Superman, there is a new god-like creature in town.
Perhaps someone needs to turn this match-up into a movie.
[1] Batman v Superman: Dawn of Justice (2016);
IMDB; http://www.imdb.com/title/tt2975590/
[2] "Tardigrade,"
Wikipedia; https://en.wikipedia.org/wiki/Tardigrade#Ecology_and_life_history
[3] Alien (1979); IMDB; http://www.imdb.com/title/tt0078748/?ref_=nv_sr_2
[4] Science
News; November 25, 2015, "Water Bears Are Genetic Mash-Ups; https://www.sciencenews.org/article/water-bears-are-genetic-mash-ups
The validity of this study has since been called into question. See the follow-up blog at http://bit.ly/1maOaCB.
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