Bdelloidea are microscopic aquatic animals that are related to roundworms, found in freshwater and moist soil. Interestingly, a male has never been observed within the species; females reproduce exclusively by parthenogenesis (without fertilization).
Coloured scanning electron micrograph (SEM) of a tardigrade (Macrobiotus sp.), or water bear. This tiny invertebrate lives in aquatic and semi-aquatic habitats such as lichen and damp moss. Magnification: when printed at 10 centimetres wide.
Water Bear Photograph - Water bears (or tardigrades) are tiny invertebrates that live in aquatic and semi-aquatic habitats such as lichen and damp moss. They require water to obtain oxygen by gas exchange.
WATER BEARS IN SPACE! The water bear, or TARDIGRADE, is so small it measures in angstroms, not millimeters. The Swedes sent some into space in The tiny critters survived the vacuum of space, the intense cold and radiation for 8 days!