Women, on average, around the globe outlive men between 6-8 years. A similar phenomenon exists in many other mammal species. What is the explanation for this phenomenon?

Some of the gaps in the life expectancy of women and men are also due to gaps in lifestyle, employment, and diet, but this is a widespread phenomenon in almost all species of mammals. Therefore the explanation must be more biological. The female hormone estrogen, secreted during a woman's fertility period, protects the liver. A long lifespan requires a robust immune system. The liver and kidneys directly affect the physiological system, and therefore, a more vital liver also provides a longer lifespan. The explanation for the phenomenon is evolutionary. Females play a crucial role in childbirth and raising offspring, and therefore nature has given them a significant physiological advantage. On the other hand, the male hormone testosterone enables a rapid increase in muscle mass. However, physical strength in the modern world is unnecessary for survival and does not increase life expectancy!