For the first time, researchers have successfully captured CT images of a woolly mammoth whole tusk. The researchers were able to perform a comprehensive scan of the tusk in its entirety – or in its entirety – using a newer clinical CT scanner. The new technology enables large-scale imaging without having to perform multiple partial scans.
“Working with precious fossils is a challenge because it is important not to destroy or damage the specimen,” said the paper’s lead author, Tilo Niemann, MD, head of cardiac and thoracic CT and radiology in the Department of Radiology at Kantonsspital Baden in Baden, Switzerland. “Even though there are different imaging methods to assess the internal framework, it was not feasible to scan an entire tusk without the need for fragmentation or at least having to do multiple scans which then had to be painstakingly stitched together. ”
The extinct woolly mammoth (Mammuthus primigenius) was the size of a modern African elephant and lived throughout Eurasia and North America. Most woolly mammoths disappeared with the end of the last Ice Age and the last specimens lived approximately 6 000 years ago. They belong to the order Proboscidea, which includes modern-day elephants as well as other extinct mammoths, mastodons, and gomphotheres.
Mammoths were covered in fur and had small ears and a small tail to alleviate frostbite. They also had tusks which they used to scratch the bark of trees, dig the ground for food and fight. Proboscidean tusks have allowed researchers to age and identify specific life-changing occurrences based on annual growth increment analysis.
Newer CT scanners have larger gantries, which are the ring or cylinder in which a patient, or in this case the tusk, is placed. The introduction of larger gantries now makes it possible to scan larger objects, which was not possible before, Dr. Niemann noted.
The defense that the researchers have examined was found in central Switzerland and excavated by the heritage and archeology office of the canton of Zug. The tusk measures a total of 206 centimeters (cm) in length, or almost 7 feet. It has a basal diameter (measurement at the base) of 000 cm – just over 6 inches. The object’s overall diameter—taking into account its helical or spiral curvature—is 80 cm, or just over 2.5 feet.
The tusks are mainly made up of two kinds of material: cementum, a bony material, and dentin, which is found under the cementum and represents the majority of the mass of the tusk. Mammoth tusks are internally structured by annual increments of dentine apposition which, when viewed in longitudinal section (as opposed to cross section), resemble cone-shaped cups stacked on top of each other . The first “cone” created by a mammoth forms the tip of the tusk, while the cone at the base of the tusk is the most recent, generated just before the animal died. Intermediate cones are formed throughout the life of the mammoth.
At the using the larger gantry CT scanner, the researchers, in collaboration with the Institute for Evolutionary Medicine at the University of Zurich.
“It was fascinating to see the composition internal mammoth tusk,” said Dr. Niemann.
Researchers found a total of 32 cones, which gives a minimum age of 32 years at the time of death. Even though the mammoth tusk is well preserved, it lacks the tip, so the estimate obtained is slightly lower than the actual age of the animal at the time of its death.
“Our mammoth had died at the age of approximately 32 years, approximately 000 ) 000 years,” Dr. Niemann said.