Welcome all to a new weekly posting from A Microbial World! Each week we will be discussing a new microorganism and how it impacts the world!

This week, we’re going to talk about one of my personal favorites- commonly called Water Bears or Moss Piglets (my favorite nomenclature)- Tardigrades! These cute little things look like this:

What are Tardigrades?

Kingdom: Animalia
Subkingdom: Bilateria
Infrakingdom: Protostomia
Superphylum: Ecdysozoa
Phylum: Tardigrada

Tardigrades were first discovered in 1773 by a German Pastor by the name of J.A.E. Goeze. Tardigrades are approximately 0.05 mm- 1.2 mm in length, with segmented bodies and 8 legs. They can reproduce via asexual reproduction and sexual reproduction and lay 1 to 30 eggs each cycle. Their diets can consist of the fluids of plants, animals and bacteria; they can eat Amoebas, nematodes and even other Tardigrades!

Why are they unique?

  • There are over 1,000 species of Tardigrades on earth
  • They live in extreme conditions from -330 to 300 degrees Fahrenheit, pressures up to 6 times the pressure of the deepest parts of the ocean, radiation and  even in the vacuum of space!
  • Tardigrades can be frozen and thawed without dying
  • They utilize a process called cryptobiosis where all metabolic processes come to a complete standstill.
  • They utilize a tiny layer of water around their bodies to keep hydrated and moving- they actually swim in their aqueous environments. When exposed to extremely dry conditions, they lose this layer and curl up into a ball-like shape called a Tun
  • Most species live in freshwater or semi-aqueous environments, however a few species live in salt water.
  • these little creatures are virtually indestructible and some theorize they have survived 5 mass extinctions over the last 500 million years.