Females live longer than males throughout the animal kingdom. Image Credit: CC BY 2.0 Jeremy Weber
A new study of mammals has shed new light on the reason females tend to outlive their male counterparts.
The fact that women tend to live longer than men has been well documented, however in animals there has long been a distinct lack of large-scale data pertaining to individual species.
Now though, a new study involving an international team of scientists has succeeded in calculating age-mortality estimates for a diverse range of over 100 species.
On average, the researchers found that females lived 18.6% longer than males in 60% of the populations analyzed - that's a much larger discrepancy than the 8% in humans.
According to lead study author Dr Jean-Francois Lemaitre, the key to understanding this difference in life expectancy lies in a combination of environmental factors (such as seasonal extremes and food availability) and sex-specific genetic variations.
One example of this can be seen in bighorn sheep - a species native to North America.
"Male bighorn sheep use lots of resources towards sexual competition, towards the growth of a large body mass, and they might be more sensitive to environmental conditions," Lemaitre explained.
"So clearly the magnitude of the difference in lifespan is due to the interaction of these sex-specific genetics, the fact that males devote more resources towards specific functions compared with females, and to the local environmental conditions."
The research compliments a previous study which indicated that the extra X chromosome in females (males have an X and a Y) may also provide a protective effect that helps them to live longer.
Source: BBC News | Comments (30)