| Description | Comfort used lebistes (guppy fish) for ground-breaking experiments on ageing at University College in London in the 1950s. His work, subsequently published in Scientific American, disproved the commonly held hypothesis of the time that animals age because they cannot grow beyond a biologically, pre-determined adult size. Guppies grow continuously and in theory, indefinitely; Comfort showed that they aged and died in the same way that mammals did. |