Prolongedpuberty may be key to a long life

“Life is but a temporary reprieve from death,” declared Simone de Beauvoir in her memoirs. But why does the length of the reprieve vary so much between species?

According to one theory, a heart beats 800 million times. Then, worn out, it stops. The smaller a creature is, the faster the beat. A mouse, clocking up 500 thumps every minute, is lucky to reach the age of two, whereas a bowhead whale, with a pumping rate in single figures, may celebrate its 200th birthday.