for National Geographic News
A woolly mammoth that died millennia ago nursed for at least six years, according to an analysis of one of its tusks. The finding raises the question: Did its mother finally get tired of being poked?
"That's an interesting question," said Adam Rountrey, a graduate student in geology at the University of Michigan in Ann Arbor who helped analyze the tusk. "At this age the tusks are not protruding very far, but sure, eventually they could get in the way."
Rountrey and his advisor, Daniel Fisher, are analyzing the chemical signatures in mammoth tusks to better understand the lives of the ancient elephantlike creatures and gain insight to the cause of their extinction.
Mammoth tusks grow a little bit every day. As growth rings reveal a tree's age, markings and chemical signatures in tusks help scientists tease out details like when a mammoth reached maturity and what it ate.
Fully grown mammoths stood 10 to 12 feet (3 to 3.7 meters) tall and weighed between 12,000 and 16,000 pounds (5,500 and 7,300 kilograms). Their tusks reached up to 10 feet (3 meters) long.
Mammoths are related to African and Asian elephants and roamed vast stretches of North America and Eurasia until their extinction about 10,000 years ago.
The cause of extinctionwhether climate change, hunting, or diseaseis hotly debated.
Fisher and Rountrey believe that understanding the life history of individual mammoths may provide the insight needed to resolve this debate.
Prior to so-called tuskology, or the analysis of tusks, the lives of mammoths were studied by researching their modern elephant cousins, said Jeffrey Saunders, a mammoth specialist at the Illinois State Museum in Springfield.
"But as scientists, paleontologists, we are all aware that a mammoth or mastodon being extinct is not the same as a living form," he said.
The tusk analysis done by Fisher and his colleagues, Saunders added, is helping scientists understand the differences between living elephants and their extinct relatives.
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