Researchers have successfully obtained full CT images of an entire woolly mammoth tusk, marking a historic milestone in the study of these ancient creatures. This remarkable feat was reported in an “Images in Radiology” article recently published in Radiology.
The significance of this accomplishment lies in the utilization of advanced clinical CT scanning technology that enables the comprehensive imaging of mammoth tusks without the need for multiple partial scans. The mammoth tusk under examination was unearthed in central Switzerland and excavated by the heritage and archaeology office of Canton Zug.
The mammoth tusk’s impressive dimensions include a total length of 206 cm, a base diameter of 16 cm, and an overall object diameter of 80 cm, including its helical curvature, which translates to just over 2.5 feet.
Through the CT images, researchers unveiled a fascinating insight into the growth of dentin apposition from the central canal, which occurred on an annual basis. A meticulous count of 32 cones within the tusk provided a minimum age estimation of 32 years at the time of the mammoth’s demise. Notably, this estimate slightly falls short of the actual age at the time of death, mainly because the tusk’s tip is missing.
Proboscidean tusks are continuously growing maxillary lateral incisors. These tusks offer a valuable window into understanding the age and specific life-altering events in a mammoth’s existence through annual growth increment analysis.
The senior author of the article, Tilo Niemann, MD, who also serves as the head of CT and heart and thoracic radiology at Kantonsspital Baden in Baden, Switzerland, acknowledged the complexities involved in working with precious fossils. He emphasized the need to avoid causing any harm or damage to these invaluable specimens.
Dr. Niemann stated, “Working with precious fossils is a challenge because it is important not to destroy or harm the specimen. Even if there exist various imaging techniques to evaluate the internal structure, it was not possible to scan a whole tusk in toto without the need for fragmentation or at least having to do multiple scans that then had to be painstakingly assembled.”
The woolly mammoth (Mammuthus primigenius), once roamed Eurasia and North America and was roughly the size of a modern African elephant. These magnificent creatures, characterized by their fur, small ears, and tails designed to prevent frostbite, sported tusks that served various purposes, including scraping bark from trees, foraging, and engaging in combat.
The vast majority of woolly mammoths disappeared at the end of the last Ice Age, with the last of their kind living approximately 6,000 years ago. Woolly mammoths belong to the order Proboscidea, a group that encompasses present-day elephants and other extinct species like mastodons and gomphotheres.
Reflecting on the mammoth under examination, Dr. Niemann noted, “Our mammoth died about 17,000 years ago.” This new achievement offers invaluable information about the lives of these ancient giants.
More information: Huber, R., Reinhard, J., Rühli, F., Kubik-Huch, R. A., & Niemann, T. (2022). CT-based Age Estimation of a Mammoth Tusk. Radiology. https://doi.org/10.1148/radiol.220265