Look at these cute tardigrades: a juvenile and an adult walking around and grazing on the green algae growing on the slide. . Tardigrades are tiny multicellular animals. The large adult here is only about 0.4 mm long, and the juvenile is roughly half that size. They hatch from eggs and grow rapidly, moulting their exoskeleton multiple times during their few-weeks-long active lifespan. . There are over 1,500 species of tardigrades, inhabiting environments from mountain tops to the deep ocean. Mos