Magazine article Science News

Parasites' Bias for Big Animals Gives Female Mammals Longevity. (Gender Gap)

Magazine article Science News

Parasites' Bias for Big Animals Gives Female Mammals Longevity. (Gender Gap)

Article excerpt

Scientists often attribute the tendency of male mammals to die earlier than females to hunting, fighting for mates, and other risky behaviors that the males engage in. In the Sept. 20 Science, however, Sarah L. Moore and Kenneth Wilson of the University of Stirling in Scotland point to another reason: Parasites infect males more often than females, apparently because the males are bigger in most mammalian species, including people.

"Our analysis suggests that parasites may be contributing to the sex difference in mortality," says Wilson.

Two lines of data originally prompted Moore and Wilson to undertake an extensive look at the scientific literature on mammalian sex differences in parasite susceptibility. First, they were aware of research showing that the hormone testosterone suppresses the immune system and thus may leave males, which make more of it than females do, particularly susceptible to parasites. "There were some studies suggesting that males tended to have more parasites than females, but there didn't seem to be any consistent pattern emerging," Wilson notes.

The second impetus derived from observations of Soay sheep on St. Kilda, an island group off the northwest coast of Scotland. Among Soay sheep, males tend to die significantly earlier than females and are more susceptible to parasitic worms that infect their gastrointestinal tracts. In experiments several years ago, Wilson's colleagues gave some sheep drugs to eliminate the infections. In his own analysis of the results, Wilson found that the mortality rates of treated males and females evened out.

So, he, along with Moore, began reviewing the scientific literature for any data that document the incidence of parasitism in male versus female mammals. The researchers ended up with more than 350 reports detailing infections with worms, arthropods, and single-cell parasites. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.