Male mammoths died in ‘silly ways’ more often than females, study finds

The New York Times

Swallowed by a sinkhole. Washed away by a mudflow. Drowned after falling through thin ice.

These are the fates that many unlucky mammoths suffered in Siberia thousands of years ago. Their well-preserved fossils have provided paleobiologists with insight into their prehistoric lives. Now, after performing a genetic analysis on the remains from the furry victims of natural traps, a team of scientists made a striking discovery: Most were male.

“In many species, males tend to do somewhat stupid things that end up getting them killed in silly ways, and it appears that may have been true for mammoths also,” said Love Dalén, an evolutionary biologist from the Swedish Museum of Natural History.

In a study published last month in the journal Current Biology, he and his colleagues analyzed DNA from nearly 100 mammoth bones, teeth and tusks, and found that about two-thirds came from males. They speculate the reason for the skewed sex-ratio may have to do with the risky behavior that young males take after leaving the protection of their mothers to live on their own.

“Old females are very knowledgeable; they know best,” he said.

The finding was an accident, according to Patrícia Pečnerová, a doctoral student at Stockholm University and lead author on the study. It came while she was entering data for a different project on mammoth genetics.

“While filling this in on the spreadsheet we saw that there were too many males, more than there should be,” she said. “We were really surprised to see there were more than twice as many males as females because there was no previous research or indication that that should be the case.”

A previous study of mammoth remains, in Hot Springs, S.D., had found that among 14 dead specimens, 13 were young adult males and only one was female. But Ms. Pečnerová’s study investigated sex ratios using genetics.

The 98 specimens that the team had analyzed came from across the northern part of Siberia and had been collected over the course of four decades.