By taking a deep look at an ancient tusk, scientists have traced the movements of a woolly mammoth and found this particular beast, over the course of its life, traveled enough distance to circle the Earth almost twice.
Published in the journal Science, researchers from the University of Alaska Fairbanks looked at the isotopes inside a 1.7-meter-long (5.6-foot) tusk from a woolly mammoth that lived in present-day Alaska just over 17,000 years ago.
Isotope analysis relies on the principle “you are what you eat.” It’s capable of providing surprisingly precise insights into an animal's life, whether it's a human or a mammoth, by looking at the concentration of certain stable isotopes and chemical elements within their tissues – especially bones, tusks, and teeth.
As an animal goes through life, certain isotopes will become incorporated into their tissues through the plants they eat. These isotopes will vary by the underlying bedrock geology of the area, as well as environmental and climatic conditions, so they can give some indication of an individual’s whereabouts and diet over the course of a lifetime.
“From the moment they’re born until the day they die, they’ve got a diary and it’s written in their tusks,” study author Pat Druckenmiller, a paleontologist and director of the UA Museum of the North, said in a statement. “Mother Nature doesn’t usually offer up such convenient and life-long records of an individual’s life.”
“It’s just amazing what we were able to see and do with this data,” adds co-lead author Clement Bataille, a researcher from the University of Ottawa
The woolly mammoth in this study is thought to have been closely related to the last group of its species that lived in mainland Alaska. Before dying around the age of 28, it appears the mammoth traveled numerous lengthy migrations across the central and northern stretches of Alaska over its lifetime.
“It’s not clear-cut if it was a seasonal migrator, but it covered some serious ground,” added Matthew Wooller, senior and co-lead author of the paper from the University of Alaska Fairbanks. “It visited many parts of Alaska at some point during its lifetime, which is pretty amazing when you think about how big that area is.”
Along with its marathon migrations, the researchers also picked up on a few other important life events. A sudden shift in isotopic signature occurred when the mammoth was around 15 years old. Based on the life of modern-day elephants, it’s likely this represented the time when the young male was kicked out of its herd and was forced to go at it alone. They also noticed a significant spike in nitrogen isotopes during its final winter, which is likely a sign he was suffering from starvation.
This new study is one of the first to reveal that woolly mammoths were experts of long-distance migrations. Despite their fame, scientists actually know very little about the behavior of the species – after all, extinction makes living things pretty hard to study – so this research provides some much-needed insight into the life of mammoths.