No species of penguin truly mates for life. There are some "divorces" each year. The divorce rate varies widely between the different species. Generally the divorce rate is lowest (at around 10%) in those species with the shortest breeding seasons (such as the Adelie) - this is probably a good tactic as they don't have to waste time finding a compatible partner each season. Conversely, penguins with a long breeding season (such as Africans) tend to have much higher divorce rates - as high as 60% in some reports.