The process of extinction involves many factors, such as weather, habitat loss, environmental toxins, disease, and shrinking population dynamics.
These factors can be analyzed to predict extinction risks and rates for endangered species. But some species may become extinct much faster than predicted because scientists have not updated the standard extinction prediction model.
Ecologists Alan Hastings at the University of California, Davis, and Brett Melbourne at the University of Colorado in Boulder have recommended a re-evaluation of the risks to wildlife based upon the proportion of males compared with females in a dwindling population, and the differences in reproductive success between individuals and birth rates in the group.
When these additional aspects are factored into risk assessments for particular species, the danger of extinction substantially increases. Missing factors such as the number of males to females and variations in the number of offspring are capable of causing unexpected large swings in the size of a population. At times, the swings may cause a population to grow, but they also may cause a population to contract.
Hastings and Melbourne contend that older extinction models could be erroneously underestimating the time to extinction. They predict that some species could go extinct 100 times sooner than expected.