🧸 Tardigrade, also called “water bear” or “moss piglet,” are part of more than 1,100 species of free-living tiny invertebrates belonging to the phylum Tardigrada. They are considered to be close relatives of arthropods. Tardigrades are mostly about 1 mm (0.04 inch) or less in size. They live in a variety of habitats worldwide, including damp moss, on flowering plants, in sand, in freshwater, and in the sea. In adapting to this wide range of external conditions, a large number of genera and species have evolved.⁠ ⁠ _____⁠ ⁠ 🔬Tardigrades have a well-developed head region and a short body composed of four fused segments, with each segment bearing a pair of short, stout, unjointed limbs generally ending with several sharp claws. The animals have no known specialized organs of circulation or respiration; the tardigrade’s body cavity (hemocoel) is filled with fluid that transports blood and oxygen (the latter of which diffuses through the animal’s integument and is stored in cells within t...