23-18 A Multi-isotope Investigation of Mammoth Diet, Habitat, and Movement Patterns in the Central Great Plains, U.S.A.

Session: Paleontology of North America (Posters)

Presenting Author:

Authors:

Abstract:

During the Last Glacial Maximum, Nebraska's Great Plains consisted primarily of wooded grasslands and parklands, whereas open spruce (Picea) forests and parklands dominated east of the Missouri River. Here we analyze bulk carbon (δ¹³C_VPDB), oxygen (δ¹⁸O_VSMOW), and strontium (⁸⁷Sr/⁸⁶Sr) isotopes in the enamel of isolated mammoth (Mammuthus) molars to compare diet and movement patterns between two late Pleistocene assemblages: one in western Iowa and Missouri (n = 17), and one in Nebraska (n = 24). In addition, we make isotopic comparisons between M. primigenius (woolly mammoth, n = 19) and M. columbi (Columbian mammoth, n = 12) molars from both assemblages. We find no statistically significant differences in C₃ diet (δ¹³C < -8.0‰), δ¹⁸O, or ⁸⁷Sr/⁸⁶Sr between assemblages, or between species in either assemblage. Carbon isotope data indicate that mammoths in both assemblages fed primarily on C₃ vegetation, although eight mammoths in Nebraska yield a mixed C₃/C₄ signal. Most identified mammoths that consumed C₄ vegetation were M. columbi, whereas M. primigenius fed almost exclusively on C₃ plants. Carbon and strontium isotopes in the Iowa and Missouri assemblage suggest six mammoths occupied areas several hundred kilometers from western Iowa where they died, while all others in the assemblage show local values. Most individuals from Nebraska also possess ⁸⁷Sr/⁸⁶Sr values that are indistinguishable from local modern plant values. However, one M. primigenius individual from southern Nebraska possesses anomalously high ⁸⁷Sr/⁸⁶Sr (0.71260), and low δ¹⁸O (15.2‰), suggesting a trek of at least 500 km to the Rocky Mountains in Colorado or Wyoming, or to the Black Hills in South Dakota. A ⁸⁷Sr/⁸⁶Sr value of 0.71155 in a tooth fragment collected in southwestern Nebraska also suggests some occupancy outside of the local area. Our data indicate that, like modern elephants, most mammoths did not travel long distances, although some individuals did.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.