The Tardigrade (Milnesium tardigradum), also known as the water bear or moss piglet, is a cosmopolitan species of tardigrade that can be found in a diverse range of environments. They can be found in every continent and habitat on Earth, but usually prefer moist places like patches of moss, giving them the nickname "moss piglets". It contains unidentified osmolytes that could potentially provide important information in the process of cryptobiosis. They feed off the moss with a nozzle-shaped mouth with tiny stylets around it to grasp their food. Tardigrades are very small and are only about the size of a pinhead. They have 8 legs with 4 claws at the end of each foot, making them look bear-like, giving them the nickname "water bears".
Tardigrades are among the most resilient animals known, with individual species able to survive extreme conditions—such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation—that would quickly kill most other known forms of life. When it becomes too dry, they curl up into a ball called a tun. They then become dormant, slowing down their metabolic rate and as the water in their bodies evaporates, they replace it with a special liquid called trelahose. This causes the brain cells and chromosomes to freeze, so the extreme temperatures don't destroy them like it would for other living things. This state is called cryptobiosis, and can last the tardigrade for up to 30 years without water. They can be triggered back to life when any sign of moisture returns. This allows them to survive long droughts in arid places like the Sahara Desert, or if they're frozen in dried ice in Antarctica. Even at the bottom of the ocean, they can survive 6,000 times more sea level pressure than any other animal. These tardigrades are so resourceful, some species can survive the extreme pressures of outer space for a short amount of time. Since tardigrades often can't find a mate to reproduce with, the females can reproduce through parthenogenesis, which doesn't require fertilization from a male.