Exploring the World of Pet Tardigrades (Water Bears)

'Water bears' is a nickname for tiny multicellular organisms that have long fascinated scientists. Officially known as tardigrades ('slow walkers'), they sport four pairs of stubby legs, giving them a resemblance to microscopic bears (albeit eight-legged ones). Tardigrades inhabit more places on Earth than humans do, so practically any damp patch of moss has the potential to harbor them. The simplest method to find and care for them, however, is to search within moist moss fragments.

Get acquainted with tardigrades. Despite their microscopic size, these creatures are incredibly fascinating! Known as water bears, tardigrades are among the most remarkable creatures on our planet, thriving in virtually every imaginable environment. They possess the astounding ability to endure: extreme temperatures ranging from -200 °C (-328 °F) to 151 °C (304 °F), being frozen in ice, extended periods without oxygen or water, intense X-ray radiation, exposure to various hazardous chemicals, boiling alcohol, the vacuum of space, and even extreme pressure equivalent to six times the ocean's deepest depths. It's important to note that tardigrades can only survive these conditions through cryptobiosis. Direct exposure to such conditions would lead to their immediate demise.

Scout for a Moist Environment Where Tardigrades Thrive. While many tardigrades inhabit aquatic environments, the most accessible location for humans to find them is in damp moss, lichen, or leaf litter. Explore forests, pond areas, or even your own backyard. Focus your search on moist areas where tardigrades are known to be active. If no moist habitat is available, consider collecting a sample of dry habitat, as tardigrades in cryptobiosis may await rehydration.

Gather a Sample of Moss or Lichen Using Tweezers. Place the sample in a paper bag or envelope to allow some moisture to evaporate. Avoid using plastic bags, as they can retain moisture and promote mold growth, obscuring your view of the tardigrades. Here are some tips:

• Collect samples from various types of moss, lichen, or leaf litter to determine tardigrade preferences.
• Tardigrades are more commonly found in soft lichen than in hard, crusty varieties. They can even inhabit the powdery lichen that grows on rocks and brick walls.

Transfer the Samples into Petri Dishes. Only a small amount of material is needed in each petri dish. If petri dishes are unavailable, use any small, transparent plastic container. Empty blister packs previously used for pills work well.

Saturate the Moss or Lichen Completely with Water. Add distilled or rainwater to the petri dish until it reaches a depth of one centimeter. Allow the moss or lichen to soak for 8 to 24 hours to activate the tardigrades.

Extract the moisture from the moss into another petri dish. By squeezing or shaking the moss, you can release the tiny creatures into the water.

Locate a low-power microscope. Tardigrades typically measure between a quarter to half a millimeter in length, making them nearly visible to the naked eye, slightly smaller than a period. A microscope with 15x or 30x magnification is sufficient for spotting them. If you lack one, consider purchasing an affordable stereo microscope online.

Search for tardigrades. Position the microscope above the petri dish and focus it on the moss. Using a strong flashlight to shine horizontally through the side of the petri dish can help illuminate the tardigrades and other organisms, causing them to appear white. Look for a creature with four pairs of short legs, moving slowly as it grasps and waves its rounded body. The hind legs face backward, which may initially resemble a tail or the creature's posterior. Here are some tips:

• If you spot a tardigrade, you've hit the jackpot. Return the water to the moss to establish a habitat for it.
• If you don't observe any tardigrades after moving the petri dish around, replace the water and try again with a different moss sample until you find one.

Offer sustenance to the tardigrade. Tardigrades feed on the juices of moss, algae, and lichen. Introduce a small amount of plant material once a month, or replace it if it begins to mold or decompose. Additional considerations include:

• Tardigrades also consume nematodes, small worm-like organisms, and rotifers, minute plankton. Opt for moist moss to provide the tardigrades with potential prey.
• Some tardigrades inhabit freshwater, while others reside in saltwater environments. Use water and vegetation sourced from the same environment where you found your tardigrades.

Keep the petri dish moist by replacing the water once it evaporates. Although tardigrades can survive in a desiccated state, it's best to ensure they remain hydrated for their well-being. Here are some additional tips:

• Dry tardigrades become smaller and motionless. They may be difficult to detect, but rehydrating them will restore their activity.

Take pleasure in caring for tardigrades. Observing them under a microscope occasionally won't bother them. If you're fortunate, you might witness fascinating behaviors like molting, egg laying, or hatching.

• Beach sediment often harbors saltwater tardigrades, so if you're keeping them as pets, collect seawater.
• If you notice colors within a tardigrade, you're peeking into its digestive system! Tardigrades are mostly transparent, allowing you to see the color of their recent meal.
• Keep in mind that some tardigrades may prey on others of their kind.