The Last Mammoths

Mammuthus primigenius, Royal British Columbia Museum. From Wikipedia Commons

During the Late Pleistocene and early Holocene, most of the terrestrial megafauna became extinct. It was a deep global-scale event. The extinction was notably more selective for large-bodied animals than any other extinction interval in the last 65 million years. Among them, the mammoths offers a very complete fossil record, and their evolution is usually presented as a succession of chronologically overlapping species, including (from earliest to latest) M. meridionalis (southern mammoths), M. trogontherii (steppe mammoths), and M. columbi (Columbian mammoths) and M. primigenius (woolly mammoths).

Wrangel Island coast. From Wikipedia Commons

From Siberia to Alaska, mammoths were widespread in the northern hemisphere and their remains inspired all types of legends. Their lineage arose in Africa during the late Miocene, and first appeared in Europe almost three million years ago. The iconic M. primigenius arose in northeastn Siberia from the steppe mammoth (Mammuthus trogontherii) and their extinction has inspired an impressive body of literature. Multiple explanatory hypotheses have been proposed for this event: climatic change, overhunting, habitat alteration, and the introduction of a new disease.

The world’s last population of woolly mammoths lived on Wrangel Island going extinct around 4,000 years ago. In contrast the mammoth population from Russia disappeared about 15,000 years ago, while the mammoths of St. Paul Island in Alaska disappeared 5,600 years ago. The Wrangel Island was a part of Beringia, an ancient landmass, that included the land bridge between Siberia and Alaska. Global sea level transgression at the end of the Pleistocene isolated Wrangel Island from the mainland and broke up Beringia. Palynological and isotopic evidence suggest that present climatic conditions and floral composition were established right after the Pleistocene-Holocene transition.

A mammoth tooth on the riverbank on Wrangel Island. Image credit; Juha Karhu/University of Helsinki

Tooth specimens are about 90% of all the mammoth material for Wrangel Island. The multi-isotopic evidence (carbon, nitrogen and sulfur in collagen) measured on Wrangel Island mammoths supports the idea that this relict population mantained a typical mammoth ecology despite climate change and decreasing genetic diversity. It has been suggested that the extinction of the Wrangel Island mammoths was possibly caused by a short-term crisis, possibly linked to climatic anomalies, however the anthropogenic influence should not be dismissed despite lack of tangible evidence of hunting.

 

References:

Laura Arppe, Juha A. Karhu, Sergey Vartanyan, Dorothée G. Drucker, Heli Etu-Sihvola, Hervé Bocherens. Thriving or surviving? The isotopic record of the Wrangel Island woolly mammoth population. Quaternary Science Reviews, 2019; 222: 105884 DOI: 10.1016/j.quascirev.2019.105884

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