Risk-taking mammoths died young

STOCKHOLM Time and again, from Kentucky to the Bering Straits, woolly mammoths appear to have died after blundering into natural traps such as thin ice, mudflows or pools. This has left palaeontologists wondering why so many of these clumsy casualties were male.

A study by researchers in Sweden and Russia has shown that two-thirds of the mammoth remains kept in museums or scientific collections come from bulls.

The scientists believe that the males were more likely to get themselves stuck in places where their corpses would be frozen or fossilised for posterity. They may not have been good at surviving, but they had a gift for posthumous self-preservation.

A team led by Patricia Pecnerova and Love Dalen, of the Swedish Museum of Natural History, analysed samples of DNA from 98 specimens across Siberia and found that 66 of them were male.

When they compared the sex ratios of mammoths from Wrangel Island in the Arctic, where the last members of the species huddled together before dying out 3600 years ago, and the vast expanse of the Russian mainland, the ratios were roughly the same.

This means the accidentproneness of male mammoths probably had little to do with their habit of moving far away into unfamiliar territory, because the Wrangel Island males were confined in a relatively small space. The more plausible theory is that they were just not as savvy as the females.

It is not, Dalen says, that the males were unusually thick. They were only doing what evolution intended – wandering off on foolhardy escapades with their teenage mates.

Much like elephants, woolly mammoths are thought to have lived in matriarchal herds dominated by females and a single bull. Shortly after the young males reached maturity, between the ages of 13 and 15, they tended to drift off in ‘‘bachelor groups’’.

Dalen said it was likely that these adolescents were driven by a strong appetite for risk, because the rewards of seizing control of a herd were so great. This mix of rash impulse and social isolation appears to have sent many males to an early grave. The Times