CURRENT RESEARCH ON THE STATURE AND PALAEODIET OF THE PRATUM-RUTSCHMAN/QUALEY MAMMOTH, MARION COUNTY, OREGON

Remains of a Columbian mammoth (Mammuthus columbi) were discovered on 26 August 1967 in a peat bog near Pratum, a small farming community northeast of Salem, Oregon. The site is located at 44^O58'35”N, 122^O50'35”W (contra Cearley and Barton 2007) in the Pudding River watershed at approximately 210 ± 10 ft elevation. Excavation at the site recovered a complete left femur, two upper 2^nd(5^th) molars, an incomplete tusk, and pelvis fragments. Morphometric analysis of the molars established the species and terminal age (the age at death) of the Pratum mammoth (Cearley and Barton 2007). Since their discovery the pelvis fragments have deteriorated to the point where morphological reconstruction is impossible, so no analysis to determine the sex of the mammoth based on pelvic morphology has been carried out. The tusk has also deteriorated since the initial discovery, but enough remains for Schreger angle and stable isotope analysis. Sequential micro-samples from the tusk have been submitted to stable isotope laboratories for δ¹⁸O and δ¹³C analysis. Because of the relatively consistent body morphology of mature mammoths it is possible to estimate the stature (shoulder height) for this animal based solely on the length of the femur. The greatest length (GL) of the Pratum femur is 1117 mm. Based on the GL ratio of Columbian and woolly mammoth humeri to femora we estimate the GL of the missing humeri for this animal to have been roughly 940 ± 15 mm. From this interpolated humeri length we estimate the shoulder height of this mammoth to have been roughly 2765 mm (9 ft. 1 in.), or approximately 2921 mm (9 ft. 7 in.) in the flesh (after methods cited in Harington et al. 1974.) Bulk samples of enamel and dentine from the Pratum molars were submitted to isotope laboratories for analysis of δ¹³C, δ¹⁵N, δ¹⁸O, and ⁸⁷Sr/⁸⁶Sr. Isotopic values of δ¹³C suggest the local vegetation and/or the palaeodiet of the mammoth. The δ¹³C value for dentine from the Pratum molars was -21.32 ± 0.2, which indicates that the mammoth was primarily consuming C3 plants (presumably cool growing season grasses). Analysis of the Pratum mammoth is an ongoing project that strives to better understand the relationship between the late Pleistocene regional extinction or extirpation of mammoths and changes in the post-LGM palaeoenvironment of western Oregon.