The world's oldest mouse - called Yoda - is four years old and still going, the equivalent of about about 136 years in a human. Yoda is a part of a breeding experiment carried out to study the way in which genes and hormones affect the rate of human aging and risks of disease late in life. As the founders of the Methuselah Mouse prize realized, healthy life extension in mice is a yardstick by which the public measures possibilities for the future of human health and longevity. Long-lived mice will mean that long-lived people are not too far off. Aubrey de Grey thinks that we could largely defeat aging in mice in a decade, given the right level of funding - certainly food for thought.