Tardigrades, also known as water bears or moss piglets, are microscopic, eight-legged animals capable of surviving extreme conditions including ionizing radiation, temperatures ranging from –273ºC to 150ºC, and decades in suspended animation. These creatures inhabit diverse environments from deep-sea sediments to mountain peaks, and it is claimed that they have the physiological capabilities to be the last beast standing in the event of a nuclear holocaust.
What makes tardigrades biologically unique?
Tardigrades are classified into their own phylum, Tardigrada, which contains approximately 1,100 known species. Unlike the phylum Chordata—which includes all animals with backbones—tardigrades possess a distinct anatomy characterized by a segmented, transparent body and four pairs of fleshy, clawed legs. Their physical appearance is described as “chubby” and “turgid.”
Tardigrades are also known as ‘water bears’ and ‘moss piglets’. These monikers go some way to describing the animals’ bumbling gait and chubby, turgid appearance.
How do water bears survive extreme environments?
The survival mechanism behind the water bear’s resilience is a state of suspended animation. When faced with environmental stressors, these creatures can dehydrate, entering a state known as a “tun.” In this stage, they can remain viable for over three decades. They can also cope with being exposed to the ionising radiation of outer-space.
How can you find and observe tardigrades?
Finding a tardigrade requires minimal equipment, though magnification is necessary due to their size of 1mm. To observe them, gather samples of moss, lichen, or soggy autumn leaves. Soak the material in water to allow any in their tun stage to rehydrate and become mobile. After wringing the material into a petri dish, use a microscope with x15 to x30 magnification—or ideally x100—to spot the creatures moving through the liquid.
Pro Tips for Your Bear Hunt
- Lighting: Use a bright light or lamp shone from the sides; this helps make the transparent, segmented bodies easier to spot against the background.
- Sample Selection: Moss on your garden wall or in your blocked gutter are locations where they can be found.
- Patience: Soak the material to increase your chances of finding one, since any in their tun stage will have had time to rehydrate and become mobile.
Frequently Asked Questions
Are tardigrades dangerous to humans?
No. They are harmless, microscopic organisms that feed primarily on bacteria and algae.
Do they live in my backyard?
Yes. They live in locations such as that clump of moss on your garden wall or in your blocked gutter.
Why can’t I see them with the naked eye?
Even a large tardigrade is just 1mm in length, so is easily missed.
Have you successfully spotted a water bear in your own backyard? Share your microscopic discoveries in the comments below, or subscribe to our newsletter for more guides on exploring the hidden world of micro-wildlife.
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