Close-up view of a mammoth tusk from the Alaska Stable Isotope Facility. To reveal growth lines, blue stain is applied. The mammoth was recorded's life by isotope analysis.One mammoth lived in Alaska 17,000 years ago and traveled so far that it could have walked straight through the entire world.A recent analysis of the preserved tusk from the woolly ice-age beast revealed that it had walked nearly 50,000 miles (80.500 km) in just 28 years. Researchers did something new to trace the steps of an adult mammoth. They cut open a mammoth's tusk and examined the chemical composition of the layers that had built up over the years.They then compared the data with chemical signatures from locations in Alaska, which were identified using small-ice age mammals' teeth. Scientists were able create a map of Alaska that shows where the mammoths lived year-to-year by matching the chemical element ratios in the different parts and the same ratios from small-mammal's teeth.Similar: Photos: An autopsy of a 40,000-year-old mammothWoolly mammoths (Mammuthus primigenius), and elephantine relatives (living, extinct), tusks store information about their habitats in an element known as strontium. The tusks absorb the element from the plants they eat. Researchers reported that strontium isotopes with different numbers or neutrons have different ratios. This allows for incremental records of where animals ate during their life stages.However, prior studies of mammoth trunks were based on vertical cores that were drilled from the tusks. These cores can reveal some of the tusk layers but not the entire record, said Matthew Wooller (study lead author, Director of the Alaska Stable Isotope Facility and Water and Environmental Research Center, University of Alaska Fairbanks) and professor in the UAF College of Fisheries and Ocean Sciences.Wooller explained to Live Science that the mammoth's tusks have cone-shaped cavities. These cavities are covered with enamel layers and look like inverted ice cream cones. This cavity is covered with new layers every day. Over years and decades, the tusks become longer as more layers are added to the bottom. It's similar to a tower of ice-cream cones growing taller as you continue inserting cones into the end of the stack. Wooller explained that to read the entire record of a mammal's life, from birth to death, one had to cut a tusk in half lengthwise. This would expose all the "ice cream cone" layers and allow for sampling.View of a mammoth tusk split at the Alaska Stable Isotope Facility, University of Alaska Fairbanks. Karen Spaleta is the deputy director of the facility. She prepares a piece mammoth-tusk for analysis. Image credit: Photo by J.R. Ancheta University of Alaska FairbanksSix scientists and one band saw.The scientists used one of the tusks of an Alaskan mammoth, which was found in the University of Alaska Museum's collection. It was collected in Alaska's Arctic Coastal Plain, above the Arctic Circle in 2010. The DNA analysis showed that the mammoth was a male. It lived approximately 17,000 years ago. The tusk measured 7.9 ft (2.4 meters). The researchers spent nearly a year trying to figure out how to divide the huge, spiraling tusk without damaging it.He said, "We might have broken a few blades along the way."The scientists separated the tusk and collected approximately 400,000 data points about the concentrations and isotopes of strontium, oxygen, and nitrogen. These data points were taken from the preserved "timeline", which covers the entire animal's life span. The mammoth as a child and a young adult was represented by the tip of the tail, while the base of its tusk reflected the final years of his life.The study authors used their data to compare it to a map showing the exact location of the mammoth's Arctic habitats. This map was preserved in the teeth and bones of small rodents that ate plants from the Pleistocene period (2.6 million to 11.700 years ago). The regional data could be used to identify the locations where the mammoth lived and visited, as small rodents such as shrews or voles are able to remain in very specific habitats all their lives.The scientists created mammoth "walks", which spanned 28 year and contained 1,133 data points. These "steps" were 40 steps, each representing roughly one year of human life.Illustration of an adult male woolly Mammoth walking up a mountain pass in Arctic Alaska 17100 years ago. This image was created from a life-size original painting by James Havens, a paleoartist who is kept at the University of Alaska Museum of the North. Image credit: Illustration by James HavensStep by stepThe mammoth was born in the lower Yukon River Basin. The mammoth moved to the interior Alaska lowlands with a herd during its juvenile years. It remained there until about 15 years of age. According to the study, the mammoth's territory grew as it reached sexual maturity at 15 years old. It then left the herd as young male elephants do.The mammoth then remained at higher elevations in Alaska's Brooks Range for its final two years of existence. Researchers reported that the animal's death was preceded by a spike in nitrogen isotopes. This could have been due to starvation or an extremely harsh winter.Wooller stated that "Until this point we didn't know this much about the movements patterns of mammoths at any time." Wooller said that future studies of mammoth tusks will provide more information about their travels. This includes how their migration patterns changed when the last ice age ended and the Earth's climate became warmer and wetter. This is a challenge Alaskan large mammals are currently facing.He said that megafauna living in the Arctic are facing significant and substantial climate change. It raises concerns about how animals will adapt to the unprecedented climate changes we are seeing in Arctic.These findings were published in Science on August 12, 2012.Original publication on Live Science
