Climate Change Gives Lousy Males a Chance to Sex

Climate change might affect us all in a nasty way; but for some perverts just waiting to sneak something to shag that's all fine.

Biologists studied the effect of decrease in rainfall pattern on mating and sexual selection in gray seals in Scotland. The reduction in freshwater pools in dry years forced females to move away from their breeding spots and from the watchful eye of the dominant male.

A greater number of inferior males managed to copulate with them, and dominant males' harems decreased in female number, triggering an increase in genetic diversity in these seal populations. Annually, from September to mid-November, pregnant female seals return to the Scottish coast to give birth. After 16 days, they mate, before setting off to sea again. Each female has preferred spots, around pools of rainwater which cool them and supply drinking water.

As females cluster around favorable sites, dominant polygamous males find it easy to chase away other males and keep for them 10 to 15 females each for mating when they are ready. In drier years, females return to the same place even if their pool is empty, but - after giving birth - they wander to find the scarce water pools. "In the very dry seasons, you get lots of movement among the females," said Sean Twiss, at Durham University, UK. That's why the dominant males cannot control their females.

Between 1996 and 2004, in one colony, only 23 males copulated in the wettest year, but 37 got pleasure during the driest, with at least 101 males in the colony each year. "A normal mating season, says Twiss, would be wet and windy throughout the 8 to 9 weeks." Global warming turned the beginning of the season increasingly dry. If climate change increases genetic diversity in Scottish grey seals, in other species could be reversed.

Photo credit: Sean Twiss