Life tables provide information on the mean survival and reproductive rates of animals of different ages and sex (Keyfitz 1968; Pollard 1973; Caughley 1977). These rates can be presented in many ways, but the key information in any life table is the proportion of animals that survive to age x(lx) and the number of recruits to the population that an animal of age x produces (mx). Life tables can easily be used to calculate the mean number of progeny per individual per generation (R0 = σlxmx), generation length (Tc = σlxmxx/R0) and the population growth rate (r = ln(R0)/Tc). When R0 = 1 each individual replaces itself and the population growth rate (r) is zero. When R0 < 1 individuals are failing to replace themselves, the population is declining and r < 0. Finally when R0 > 1 individuals are more than replacing themselves and the population increases in size (r > 0). Life tables now exist for a wide range of species and are much used in population and evolutionary ecology to construct models of population dynamics, to estimate whether a population is increasing or decreasing in size and to estimate the strength of selection (Caswell 1989, 2001; Brault and Caswell 1993). If a population biologist wanted to find out details about a species' population biology he would almost certainly look for an available life table before doing anything else.