Anti-ageing research often uses short-lived model species such as mice. But these species age in a very different way to us, so they may not tell us all that much about boosting our own lifespans.
Women often say their periods begin at the same time as their friends'.
Going naked in public has its own benefits.
Scientists of all kinds turn to computer models to investigate questions they can't get at any other way. Here's how models work and why we can trust them.
From dancing to giving presents, animals have evolved some effective and surprisingly familiar ways of wooing a mate.