16 Aug 2021

Mammoth journey: Tusk isotope study reveals Kik's roaming lifestyle

12:42 pm on 16 August 2021

A woolly mammoth named Kik that roamed Alaska 17,000 years ago covered enough ground in its 28-year lifetime to nearly circle the globe twice, an analysis of one of its tusks suggests.

Woolly mammoth set in a winter scene environment. 16/9 Panoramic format. Realistic 3d illustration.

Photo: LEONELLO CALVETTI/SCIENCE PHOTO / LCL / Science Photo Library via AFP

The findings, detailed in a study published Thursday in the journal Science, show how the male mammoth went through infancy and youth as part of a herd, but died alone from starvation in Alaska's northernmost mountains.

One of the report's authors, Clément Bataille from the University of Ottawa, told Morning Report the team analysed the chemical signatures from isotopes to find out where the mammoth had travelled.

"They come basically from the type of rock that you're living on so basically as the mammoth is roaming on the landscape and he's roaming on different sort of geology, the geology gives to the tusk a specific sort of signatures that we can match to that particular location."

"We could figure out some things about the environment - so, what kind of season he was walking through - and also something about the health of the mammoth."

Co-lead author Matthew Wooller, from University of Alaska at Fairbanks, said it was one of the first insights into the life history of an Arctic woolly mammoth.

To generate more than 400,000 data points for the study, the scientists sliced open the tusk, exposing the layers that were added as the animal grew. Those layers, Wooller said, were like "sugar ice cream cones stacked one inside of each other."

In its early years, the mammoth - named Kik by researchers after the river where its remains were found - moved around the area that is now the Lower Yukon River region, Wooller said.

Though glaciers extended far south at the time, much of Alaska, including that region, was glacier-free. Alaska areas that are now boreal forest were grassy steppe-like terrain, ideal for grazers such as woolly mammoths, he said.

"It was probably hanging out with the herd, with its mother and other members of the herd," Wooller said.

Mat Wooller, director of the Alaska Stable Isotope Facility, kneels among a collection of some of the mammoth tusks at the University of Alaska Museum of the North.

Photo: JR ANCHETA / University of Alaska Fairbanks / AFP

At age 15 or 16, the mammoth dramatically increased the distance and range of its travels, heading periodically to points much farther north and higher in elevation.

Bataille said the distance walked - nearly enough to circle the globe twice - was more than a modern elephant would normally walk but similar to the amount a human might walk in their lifetime, an impressive feat considering its 28-year lifespan.

"What was really staggering was kind of the extent of movement that this animal was going through, covering basically the entire state of Alaska," Bataille said.

"That was just much more than what we were expecting - the animal was supposed to stay like, on the little river valley there and move back and fort but we found that he was moving huge, huge trips around the landscape there."

It's likely that the mammoth left the herd then, Wooller said. Its behaviour mirrored patterns in some modern elephant herds, in which maturing males are "encouraged, and I would put inverted commas around that word," to strike off on their own, he said.

In its later years, the mammoth roamed some routes that caribou use today, Wooller said. It is possible that the mammoth, as it travelled seasonally to find food, shared migration paths with ancient caribou, he said.

Its demise likely came at the Arctic gravel bar where its remains were found in 2010. The combination of two tusks and a partial skull there "gives us pretty good confidence that that's where it died," Wooller said.

At the end, it endured nutritional stress, the tusk analysis showed. "It looks like in its last year of life it slowed down to not much moving around," Wooller said. "We have kind of a smoking gun of what killed it."

The study does more than just satisfy curiosity about extinct Ice Age creatures. It is relevant to species living in today's rapidly changing Arctic, Wooller said.

"Our work helps shed a light on environmental concerns we have about modern animals like polar bears and caribou that live in the Arctic today," he said.

- Reuters / RNZ

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