New research has been done to show that killer whale grandmothers who no longer can reproduce increased the survival rate of their grand-offspring. This may be due to the fact that these killer whale grandmothers have more time to focus on their grand-offspring if they do not have offspring themselves to take care for. Research shows that female killer whales that are no longer reproducing provide an important leadership role. Male killer whales often have a shorter life expectancy, with many not living beyond 30 years. On the other hand, female killer whales don't stop reproducing until they're in their 30s-40s and can live decades after that as well. The findings from this research helps us better understand the factors that are driving the reproductive success of the whales.