Water bear. Coloured scanning electron micrograph (SEM) of a water bear (Macrobiotus sapiens) in moss. Water bears (or tardigrades) are tiny invertebrates that live in aquatic and semi-aquatic habitats such as lichen and damp moss. Macrobiotus sapiens is an omnivorous species that feeds on mosses, algae and bacteria. Water bears are found throughout the world, including regions of extreme temperature, such as hot springs, and extreme pressure, such as deep underwater. They can also survive the high levels of radiation and vacuum of space. Magnification: x200 when printed at 10 centimetres wide.