Professor Fisher's current research focuses on the paleobiology and extinction of mastodons and mammoths, elucidated by studies of growth increments and compositional (isotopic and elemental) time series sampled from their tusks and cheek teeth. Fieldwork associated with these projects involves many Pleistocene proboscidean sites in North America (especially the Great Lakes region) and in Siberia. North American occurrences include well preserved mastodon and mammoth skeletons, some showing evidence of human association (hunting, carcass processing). Siberian occurrences include permafrost-derived carcasses with extensive soft-tissue preservation, representing mammoths and other elements of the Mammoth Steppe fauna. Investigations of how teeth record details of animal physiology and life history are supported by studies of tooth formation processes in humans and other mammals. Additional projects have explored use of stratigraphic data in phylogenetic inference; digestive physiology of crocodilians; modes of growth of receptaculitid algae; comparative anatomy, skeletal crystallography, and phylogeny of stylophoran echinoderms; and functional morphology, phylogeny, and macroevolutionary patterns of horseshoe crabs.

Field(s) of Study
Paleobiology
Taphonomy
Phylogenetic Inference