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Last Updated: Thursday, 14 December 2006, 15:30 GMT
More sex for climate change seals
Female seals are being forced to travel further for fresh water
Male seals are taking advantage of the effects of climate change by having more sex, according to a new study.

Rising temperatures and reduced rainfall means female grey seals have to travel further to find fresh water.

This removes them from the watchful eye of dominant males, allowing weaker seals to seize the opportunity.

The research was conducted by Dr Sean Twiss, from Durham University, who studied a grey seal colony on the remote Scottish Island of North Rona.

These findings show that climate change, whilst endangering many species, could also help to increase the genetic diversity of some species
Dr Twiss, Durham University

Dr Twiss said: "Grey seals are typically polygamous, with the more dominant males mating with approximately 10 to 15 females which they guard from other males within their territory.

"These males' ability to dominate is easy when rainwater pools are abundant and females cluster in a small geographical area, but during dry seasons the area in which the females are located becomes too big and they can no longer successfully keep an eye on them all.

"The increased movement amongst the females allows the weaker males to mate and results in more males contributing genetically to the next generation."

Over nine years, Dr Twiss and his colleagues recorded a 61% increase in the number of males contributing to the genetic pool.

Genetic diversity

In the UK grey seals gather on remote islands for 18 days during October and November each year for mating.

This autumnal breeding season would normally be wet and windy but the researchers recorded unusually dry starts to the seasons between 1996 and 2004.

Dr Twiss said: "These findings show that climate change, whilst endangering many species, could also help to increase the genetic diversity of some species, giving a leg up, or over, to males who normally wouldn't be so successful."

The research was published in the Royal Society's Biology Letters journal.

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