Seethaler was involved in numerous projects, in particular to research historical ethnological collections. In particular, this includes provenance research on
human remains . In addition to examining possible contexts of injustice in collections from the colonial and Nazi era, he researches the history, motifs and social mechanisms of collecting, particularly non-European cultural goods, up to the present day. His provenance research on the skulls of indigenous Australians in the anthropological collection of the
Berlin Society for Anthropology, Ethnology and Prehistory and from
Australia and
Namibia in the collections of the
Charité in the "Charité human remains project" formed the start of a broad study of the origins of human remains in German museums and collections. This research formed a basis for the creation of a uniform guideline for dealing with human remains in public collections in Germany. In this context there was restitution of skulls to the countries of origin. The rediscovery of four presumably indigenous skulls from Canada, in which Seethaler was involved in his role as archive director, also attracted international attention in 2020. The Canadian doctor
William Osler brought the skulls to Germany at the end of the 19th century and gave them to
Rudolf Virchow in Berlin. In addition to his work with historical collections, Seethaler was involved in a number of interdisciplinary research at the interface between the humanities and the natural sciences. In 2010, together with
Carsten Niemitz and
Benjamin P. Lange, he organized the 11th Annual Conference on "Human Behavior in Evolutionary Perspective" in Berlin. == Exhibition projects ==