The Remarkable World of Tardigrades
Nature's Microscopic Survivors
When it came time for me to pen another blog post, I found myself pondering various topics until an enlightening Zoom call with my relatives from Down Under over the Christmas holidays. During our virtual gathering, my two young nephews, enthusiastically delved into the fascinating world of microscopic creatures known as Tardigrades, affectionately referred to as 'Water Bears.' This newfound curiosity sparked my interest, prompting me to embark on a research journey into the captivating realm of these diminutive yet intriguing life forms.
To kick things off, let's start with a little factoid: the name "Tardigrade" originates from the Latin words "tardus" (meaning 'slow') and "gradior" (meaning 'step' or 'walk'). Originally used as an adjective to describe tortoises, this term has been attributed to these microscopic wonders since the 1800s. It's worth noting that "Tardigrade" essentially means "slow-paced" or "sluggish."
Let's explore some literary references to this term:
In 1850, Joses Badcock wrote in "Botany; or, Phytology": "Each tendril ending in a perfect claw, / Obeys the whole routine of Nature's law; / Transforms each sinus to a sylvan shade, / Though p'rhaps its force is rather tardigrade."
In George Eliot's "Romola" (1863): "He ran on into the piazza, but he quickly heard the tramp of feet behind him, for the other two prisoners had been released, and the soldiers were struggling and fighting their way after them, in such tardigrade fashion as their hoof-shaped shoes would allow—impeded, but not very resolutely attacked, by the people."
In Richard S. Conde's "The Metronome" (2001): "In sorrow, its voice is tardigrade but loud, dragging time at a snail's pace before our eyes."
The Moss Piglet - what a cute name!
The world of the moss piglet is incredible. It’s a real-life creature despite its diminutive size. These microscopic marvels possess legs (eight of them), eyes, nerves, muscles, and a snout-like mouth. Each leg is adorned with four to eight claws or digits, giving them an appearance reminiscent of the hookah-smoking caterpillar from "Alice in Wonderland." While tardigrades exude an aura of cuteness, they also possess an astounding resilience, capable of surviving even the harsh conditions of outer space.
In the words of my nephews, "Tardigrades are amazing because they can thrive in any climate: from deserts and volcanoes to the depths of the ocean and even the vacuum of space! They've been around for as long as the dinosaurs, yet despite over 1300 species, only three are present in the fossil record. And let's not forget, they're undeniably cute!"
Tardigrades are semi-aquatic beings, equally at home in aquatic and terrestrial environments. They can be found in oceans, lakes, mountains, forests, and even sand dunes, inhabiting locations ranging from frigid Antarctic glaciers to active lava fields. Moss is a common abode for these remarkable creatures.
When it comes to their diet, most tardigrades feed on algae and flowering plants by piercing plant cells and extracting their contents through their tube-shaped mouths, known as the "bucco-pharyngeal apparatus." However, some tardigrades take a carnivorous route and may feast on other members of their kind.
Tardigrades are nature's pioneers, venturing into new and often inhospitable environments, providing sustenance for larger creatures that follow in their wake. Some scientists speculate that tardigrades may have been among the first animals to transition from the ocean to terrestrial habitats.
Survival Secrets
One of their key survival secrets lies in a unique protein called Dsup, short for "damage suppressor," which shields their DNA from harm caused by factors like ionizing radiation, prevalent in soil, water, and vegetation. Another astonishing survival mechanism is cryptobiosis, a state of dormancy triggered by dry conditions. In this state, tardigrades expel water from their bodies, retract their extremities, curl into a compact ball, and remain dormant until conditions improve.
Interestingly, tardigrades also exhibit unusual mating habits. Depending on the species, they may reproduce both sexually and asexually. Some species involve males depositing sperm within the cuticle of a molting, egg-carrying female during an hour-long mating process. Certain females shed their cuticles before laying their eggs, which are later fertilized by males. The hatching of eggs takes around 40 to 90 days, depending on whether they have been in a desiccated state.
What's truly remarkable is that you can keep tardigrades as pets without the need for a purchase. Many tardigrades are aquatic, and you can find them in your local environment. Here's how:
Locate a mossy environment near your area.
Collect a small, damp sample and place it in a paper bag or envelope to allow some moisture to dissipate (avoid plastic bags, as they can encourage mold growth).
Sample various types of moss, lichen, or leaf litter to see which tardigrades prefer. Soft lichen is more likely to host tardigrades than hard, crusty lichen. They can even be found in powdery lichen on rocks and brick walls.
Collect a sample from a dry habitat (if no other options are available), as tardigrades in extreme hibernation (cryptobiosis) may await rejuvenation with water. Add water to keep the moss wet for about a day, allowing the water bears to become active.
Squeeze out some water onto a clear slide or petri dish, and observe the results under a low-power microscope. Tardigrades typically measure between a quarter to a half a millimeter in length, just on the cusp of human visibility.
To enhance visibility, shine a powerful light from a torch horizontally through the petri dish or slide. This will illuminate the tardigrades, making them appear white. Look for creatures with four pairs of stubby legs, moving in slow-motion as they navigate their blob-like bodies. The last pair of legs faces backward, resembling a tail or the end of their body.
With hundreds of species in the phylum Tardigrada known for their remarkable hardiness, they may outlast other life forms on Earth, enduring as long as the sun continues to shine. Their uncanny ability to thrive in extreme conditions has captivated scientists, who believe that tardigrades could hold the key to human survival. Ongoing research into these resilient micro-animals may offer insights that prove invaluable for medical procedures and space exploration alike.
Enjoy this incredible other world - a great wee pet!
Saranne Bish is a consummate communicator and empathetic High Life Higland Ranger, with a life devoted to environmental stewardship. Her transition in 2002 from Ecological Surveying to Countryside Ranger for Nairn, Badenoch, and Strathspey marked a significant shift in her career. Saranne excels in educating and engaging with diverse audiences about the natural world, blending scientific knowledge with a warm, accessible approach. Her passion for conservation is matched by her skill in inspiring others, fostering a collective commitment to protecting our planet's fragile ecosystems. Her ability to connect with people and nature alike makes her a true advocate for the environment.