10 Interesting Facts about Tardigrade

It is surely the stuff of science fiction: An extraordinary being arrives on Earth that can withstand a tortuous array of conditions: boiling, freezing, tremendous atmospheric pressure, near total dehydration, and exposure to massive amounts of ionizing radiation. While many joke that “cockroaches would be the only thing to survive an extreme global nuclear war”, in fact, cockroaches would not.  These creatures would. They are also the only life form known to be able to survive the near vacuum of space for extended periods. (Note: humans can actually survive the near vacuum of space for about 90 seconds without long term damage, but we have nothing on this creature.) They can lie dormant for 10-100 years and then come back to life with a drop of water. When it comes to durability, nothing on Earth can match the very real “Water Bear”- a tiny creature the size of a grain of sand (averaging about a millimeter long) that is often lauded as the toughest creature on planet Earth.

1. Tardigrades are small, really tiny, actually micro animals with segmented bodies. They are usually water-dwelling creatures but can be found in a myriad of places like Antarctic ice, deep in ocean beds to a depth of 14,000 ft, high up in Himalayas at a height of 20,000 ft, tree barks, moss and more!

2. They have 8 legs (4 pairs) and each leg has 4 to 8 claws that resemble the claws of a bear. This is why they have earned the name ‘Water Bear’ but they are also known by the name ‘Moss Piglet’ because they are also found in moss.

3. More than a 1,150 species of Tardigrades have been identified so far since 1778.
4. So if the tardigrade is so resilient, why isn’t everything on the planet coated with a thick layer of them?  Well, it turns out the natural life span of the tardigrade is just about a year, unless they are dehydrated.  In that case, obviously the record is currently about 120 years as listed above.

5. Tardigrade babies are all born with a full range of adult cells. They grow not by cell division. Their cell simply expand in size.

6. When the tardigrade emerges from its egg, it actually has all its adult cells and does not grow in terms of number of cells.  It does increase in size, though, as individual cells enlarge.

7. Because their hardiness verges on indestructibility, this little bear’s ability to survive beyond Earth’s atmosphere encourages speculation that they could have potentially come from outer space, a belief known as transpermia.  Whatever the case, the first known tardigrade seems to have popped up on Earth around 530 million years ago.

8. Most tardigrades eat plant matter and bacteria, although some prey on nematodes (tiny worms) or other creatures, foraging around with their signature lumbering gait.

9. Although tardigrades generally consist of males and females, some species have been identified as parthenogenic (a form of asexual reproduction) or even hermaphroditic.  The tardigrade’s survival and adaptability strategies are so effective it shouldn’t be surprising that its mating method is just as efficient. In most observed species, when the female molts, she leaves some eggs in her cast-off skin, after which the male fertilizes them with sperm and then lumbers on his way.

10. Do you want to see a Water Bear for yourself? Or is your kid on the market for an awesome science project? You’re in luck, because anyone with a microscope can observe tardigrade behavior up close and personal. Just find a piece of moss, soak it in some spring water in a petri dish and see if you can spot a tardigrade among the creatures that begin to animate your scope’s visual field.