It's one small step for water bears, one giant leap for animal-kind. Tiny animals called tardigrades — better known as water-bears — have become the first animals to survive the cruel vacuum, intense cold and radiation of space without a spacesuit. Water bears were already known to be among the toughest critters alive. When not flying in a low Earth orbit, they prefer to spend their days in water, perhaps on a beach or a dewy patch of moss.