Water bear tun (Milnesium tardigradum). Coloured scanning electron micrograph (SEM) of a water bear in its dormant state, known as a tun. Water bears (or tardigrades) are tiny invertebrates that live in aquatic and semi-aquatic habitats such as lichen and damp moss. In dry conditions, they can enter a cryptobiotic state of dessication to survive. In this state, water bears can survive for up to a decade. This species is a carnivore that feeds on nematodes, rotifers and protozoa. This specimen originated from moss samples in Tubingen, Germany. 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: x833 when printed 10cm wide.