Verdugo Hills High School

Water Bears — animals that live in your backyard

Imagine an animal able to survive any harsh condition known to man. This animal actually exists right in your own backyard! Tardigrades, also known as Water Bears, are water-dwelling, microscopic animals that inhabit nearly every terrain in the world, such as mountaintops, the deep-sea, tropical rainforests, and the Antarctic. They have been known for their ability to survive extreme conditions otherwise fatal to all other known life forms on this planet. Water Bears consist of eight legs each. Fortunately, these animals are harmless and only consume plant fluids and microscopic animals, such as rotifers or other tardigrades.

Color enhanced scanning electron micrograph of a Water Bear. Credit: Eye of Science/Science Source
Color enhanced scanning electron micrograph of a Water Bear. Credit: Eye of Science/Science Source

When adapting to environmental stress, such as dehydration, Water Bears enter a state of Cryptobiosis. While in this state, they are curled up into a dry, lifeless ball with their metabolism suspended, making them able to survive without water or food. Some can survive being frozen at temperatures as low as -300 degrees. In their “tun-like” state, “the damaging effects of freezing cannot happen,” says Dr. Mark Siddall, a parasitologist and curator at the American Museum of Natural History. “It protects against heat because the water inside cannot turn into a gas that expands,” he continues. This lack of water in their cells during Cryptobiosis is one of the main reasons they can survive in such harsh conditions. According to, “Tardigrades have been revived from this state after more than 100 years and shown signs of life!” When sent to space in 2007, by the European Space Agency, tardigrades were shown to have survived the exposure of radiation.

There are many different species of tardigrades still being discovered today. Most of them are found in mosses, freshwaters, or ice. You can even have a tardigrade as a pet! All you need to do is collect a clump of moss or lichen, place it in a shallow dish, and soak it in water for 3-24 hours. After that, shake or squeeze the moss or lichen over another dish to collect trapped water and examine the water with a stereo microscope. Once you find a tardigrade, use a micropipette to transfer the water to a slide for a larger and clearer observation of it. There are thousands of unknown tardigrade species we’ve haven’t discovered yet, meaning you might find a new species right outside your doorsteps!