Giant Beaver (Castoroides) Palaeoecology Inferred from Stable Isotopes

Author

Tessa Plint, The University of Western OntarioFollow

Degree

Master of Science

Program

Geology

Supervisor

Fred J. Longstaffe

Abstract

Stable isotope analysis was used to explore unresolved questions about the palaeoecology of the extinct Pleistocene giant beaver (Castoroides). The δ¹³C, δ¹⁵N, and δ¹⁸O of bone collagen and structural carbonate from enamel served as proxies for palaeodiet and palaeoclimate. A new baseline for freshwater and terrestrial plant δ¹³C and δ¹⁵N was utilized in a mixing model (SIAR) to assess rodent feeding niche. SIAR analysis indicated that Castoroides’ consumed a diet of predominantly macrophytes, making them reliant on wetland habitat for food. Based on isotopic data for potential modern analog species (Castor and Ondatra), SIAR also indicated that Castor and Castoroides occupied complementary dietary niches, allowing them to share habitat space throughout the Pleistocene. The δ¹³C and δ¹⁸O of Castoroides’ ever-growing incisors also recorded seasonal fluctuations in diet and climate. Wetland loss due to climate change during the Last Glacial Maximum, and increased competition for habitat, probably factored into Castoroides’ extinction.

Recommended Citation

Plint, Tessa, "Giant Beaver (Castoroides) Palaeoecology Inferred from Stable Isotopes" (2016). Electronic Thesis and Dissertation Repository. 4236.
https://ir.lib.uwo.ca/etd/4236