Light micrograph (DIC) of a Rotifer Lepadella sp. Rotifers are the smallest animals on earth. Rotifers have existed for at least 35 million years and they only live for about 1-2 weeks. Under tough conditions (e.g. drought), rotifers can go into a desiccated state as a cyst or egg that can survive for decades without any signs of aging. The cysts can be carried by the wind and allow the rotifer to spread and escape harmful conditions. Once it finds water, the rotifers come back to life. Magnification: x425 when printed at 10 centimetres wide at its longest edge.