Tardigrades

Okay, what the heck are tardigrades? Well gang, they are amazing creatures that prove that life can survive just about anything and, more importantly, their existence suggests that life could be not only on Mars but some moons of Jupiter and Saturn.

According to Wiki, Tardigrades also go by name of Water Bears or Moss Piglets. They are water-dwelling, eight-legged, segmented micro-animals. The name 'Tardigrade' essentially means slow stepper. They are found just about everywhere.

What makes these tiny creatures so interesting is that they can survive in just about any condition by a fascinating hibernation mechanism. They have survived temperatures from IK to 420 K, that's from -272 C or -458 F to 150 C or 300 F. These temperatures would kill most other living things. They also survive pressures six times greater than in the deepest ocean trenches. They can also survive radiation thousands of times that which would kill any other life. And, They have been known to survive in hibernation for over 30 years.

NASA astronauts took them up the International Space Station and stuck them outside where they were exposed to vacuum and radiation. Despite this harsh treatment, they were hydrated and found to be still alive.
A Tardigrade survives by shriveling up into a protective ball that can then be hydrated back to full functionality. They do this by a process known as crytobiosis, which allows them to suspend their metabolism and be dehydrated without harm. Apparently, they have been using this technique to survive from ancient times. They are essentially living fossils.

These are not like single celled creatures. They're not very large, only 0.3 to 0.5 cm, but they have at least 40,000 cells. The interesting part is that there are male and female forms of this amazing creature. They have claws to aid them in movement and they do have brains. So, this is not a simple creature, and yet it can survive harsh conditions, even in space. This makes it a logical candidate for a extraterrestrial life form.

They are not an extremophile, a creature that can endure anything. Most of these are bacteria, and they have been found in the worst possible locations for life, such as in a deep ocean or near a volcanic vent under the sea. These kind of creatures could exist just about anywhere. But, what makes the Tardigrade so interesting is that it's a complex creature that could exist in outer space.

Thanks for reading.