How much do you know about Tardigrades?



9 Questions

What is another name for tardigrades?

What is the maximum atmospheric pressure that tardigrades can survive?

What is the temperature range that tardigrades can survive?

What is the main reason tardigrades are considered the toughest animals on Earth?

What is the average length of tardigrades when they are fully grown?

What do tardigrades feed on?

What is the closest known relative of tardigrades?

What is the size range of tardigrade genomes?

What is the role of tardigrades in developing environments?


Tardigrades, also known as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals found in diverse regions of Earth's biosphere. They are among the most resilient animals known, able to survive extreme conditions such as exposure to extreme temperatures, extreme pressures, air deprivation, radiation, dehydration, and starvation that would quickly kill most other known forms of life. Tardigrades have survived exposure to outer space. They have about 1,300 known species in the phylum Tardigrada. Tardigrades are usually about 0.5 mm long when fully grown. They are short and plump, with four pairs of legs, each ending in claws or suction disks. Tardigrades are prevalent in mosses and lichens and feed on plant cells, algae, and small invertebrates. They lack several Hox genes and a large intermediate region of the body axis. They are oviparous and fertilization is usually external. Tardigrades are able to suspend their metabolism and survive in a dehydrated state up to five years, or longer in exceptional cases. Their ability to remain desiccated for such long periods of time was thought to be dependent on high levels of the nonreducing disaccharide trehalose. However, it has been seen that in both tardigrades and bdelloid rotifers, there is only a partial capability to synthesize trehalose in quantities that may contribute to desiccation tolerance. Tardigrades are able to survive in extreme environments that would kill almost any other animal.Tardigrades: The Toughest Animals on Earth

  • Tardigrades, also known as water bears or moss piglets, are microscopic animals that can survive extreme conditions.
  • Tardigrades can survive extreme temperatures ranging from -273°C to 151°C.
  • They can also survive pressures of up to 6,000 times atmospheric pressure, and radiation levels that are hundreds of times higher than lethal doses for humans.
  • Tardigrades are the first known animal to survive after exposure to outer space.
  • In 2007, dehydrated tardigrades were taken into low Earth orbit on the FOTON-M3 mission and were exposed to the hard vacuum of outer space for 10 days.
  • More than 68% of the subjects were reanimated within 30 minutes following rehydration, although subsequent mortality was high.
  • In May 2011, Italian scientists sent tardigrades on board the International Space Station and their conclusion was that microgravity and cosmic radiation did not significantly affect their survival.
  • Tardigrades are either most closely related to Arthropoda and Onychophora, or to nematodes.
  • The only known fossil specimens of tardigrades are those from mid-Cambrian deposits in Siberia.
  • Tardigrade genomes vary in size, from about 75 to 800 megabase pairs of DNA.
  • The genome of Ramazzottius varieornatus, one of the most stress-tolerant species of tardigrades, was sequenced in 2015.
  • Tardigrades work as pioneer species by inhabiting new developing environments, attracting other invertebrates to populate that space, while also attracting predators.


Are you ready to test your knowledge on the toughest animals on Earth? Take our quiz on Tardigrades, also known as water bears or moss piglets, and discover amazing facts about these micro-animals that can survive extreme conditions such as exposure to outer space, extreme temperatures, pressures, radiation, dehydration, and starvation. Challenge yourself and see how much you know about these resilient creatures that inhabit diverse regions of Earth's biosphere and are able to suspend their metabolism and survive in a dehydr

Ready to take the quiz?

Start Quiz