Publications

Eric Guiry, Ryan Kennedy, David Orton, Philip Armitage, John Bratten, Charles Dagneau, Shannon Dawdy, Susan DeFrance, Barry Gaulton, David Givens, Olivia Hall, Anne Laberge, Michael Lavin, Henry Miller, Mary F. Minkoff, Tatiana Niculescu, Stéphane Noël, Barnet Pavao-Zuckerman, Leah Stricker,  Matt Teeter, Martin Welker, Jennifer Wilkoski, Paul Szpak & Michael Buckley

Abstract

While the impacts of black (Rattus rattus) and brown (Rattus norvegicus) rats on human society are well documented—including the spread of disease, broad-scale environmental destruction, and billions spent annually on animal control—little is known about their ecology and behavior in urban areas due to the challenges of studying animals in city environments. We use isotopic and ZooMS analysis of archaeological (1550s–1900 CE) rat remains from eastern North America to provide a large-scale framework for species arrival, interspecific competition, and dietary ecology. Brown rats arrived earlier than expected and rapidly outcompeted black rats in coastal urban areas. This replacement happened despite evidence that the two species occupy different trophic positions. Findings include the earliest molecularly confirmed brown rat in the Americas and show a deep ecological structure to how rats exploit human-structured areas, with implications for understanding urban zoonosis, rat management, and ecosystem planning as well as broader themes of rat dispersal, phylogeny, evolutionary ecology, and climate impacts.

He Yu, Alexandra Jamieson, Ardern Hulme-Beaman, Chris J. Conroy, Becky Knight, Camilla Speller, Hiba Al-Jarah, Heidi Eager, Alexandra Trinks, Gamini Adikari, Henriette Baron, Beate Böhlendorf-Arslan, Wijerathne Bohingamuwa, Alison Crowther, Thomas Cucchi, Kinie Esser, Jeffrey Fleisher, Louisa Gidney, Elena Gladilina, Pavel Gol’din, Steven M. Goodman, Sheila Hamilton-Dyer, Richard Helm, Jesse C. Hillman, Nabil Kallala, Hanna Kivikero, Zsófia E. Kovács, Günther Karl Kunst, René Kyselý, Anna Linderholm, Bouthéina Maraoui-Telmini, Nemanja Marković, Arturo Morales-Muñiz, Mariana Nabais, Terry O’Connor, Tarek Oueslati, Eréndira M. Quintana Morales, Kerstin Pasda, Jude Perera, Nimal Perera, Silvia Radbauer, Joan Ramon, Eve Rannamäe, Joan Sanmartí Grego, Edward Treasure, Silvia Valenzuela-Lamas, Inge van der Jagt, Wim Van Neer, Jean-Denis Vigne, Thomas Walker, Stephanie Wynne-Jones, Jørn Zeiler, Keith Dobney, Nicole Boivin, Jeremy B. Searle, Ben Krause-Kyora, Johannes Krause, Greger Larson & David Orton

Abstract

During recent decades, the health of ocean ecosystems and fish populations has been threatened by overexploitation, pollution and anthropogenic-driven climate change. Due to a lack of long-term ecological data, we have a poor grasp of the true impact on the diet and habitat use of fishes. This information is vital if we are to recover depleted fish populations and predict their future dynamics. Here, we trace the long-term diet and habitat use of Atlantic bluefin tuna (BFT), Thunnus thynnus, a species that has had one of the longest and most intense exploitation histories, owing to its tremendous cultural and economic importance. Using carbon, nitrogen and sulphur stable isotope analyses of modern and ancient BFT including 98 archaeological and archival bones from 11 Mediterranean locations ca. 1st century to 1941 CE, we infer a shift to increased pelagic foraging around the 16th century in Mediterranean BFT. This likely reflects the early anthropogenic exploitation of inshore coastal ecosystems, as attested by historical literature sources. Further, we reveal that BFT which migrated to the Black Sea–and that disappeared during a period of intense exploitation and ecosystem changes in the 1980s–represented a unique component, isotopically distinct from BFT of NE Atlantic and Mediterranean locations. These data suggest that anthropogenic activities had the ability to alter the diet and habitat use of fishes in conditions prior to those of recent decades. Consequently, long-term data provide novel perspectives on when marine ecosystem modification began and the responses of marine populations, with which to guide conservation policy.

Ardern Hulme-Beaman, David Orton & Thomas Cucchi

Implications

• Historical evidence indicates that brown rats went through a series of human-influenced and/or controlled-breeding events at different times and locations: Japan in the 1600 to 1700s, Europe in the early 1800s, and North America in the mid-1800 to early 1900s.

• The European and Japanese controlled-breeding events may be considered domestication events, whereas the later events from the mid-1800s onward might be considered selective breeding of an already domesticated animal.

• Each event appears to have been for a different purpose: Japanese rats were pets and ornamental; early European breeding was in the first instance for blood sports and food sources for captive carnivores; North American selective breeding was for laboratory use.

• Modern examination of domestic brown rats has almost exclusively focused on laboratory strains, which stem from a limited source and there has been little to no exploration of pet or fancy rat populations.

Emily Puckett, David Orton & Jason Munshi-South

Abstract

Phylogeography and zooarchaeology are largely separate disciplines, yet each interrogates relationships between humans and commensal species. Knowledge gained about human history from studies of four commensal rats (Rattus rattus, R. tanezumi, R. exulans, and R. norvegicus) is outlined, and open questions about their spread alongside humans are identified. Limitations of phylogeographic and zooarchaeological studies are highlighted, then how integration would increase understanding of species’ demographic histories and resultant inferences about human societies is discussed. How rat expansions have informed the understanding of human migration, urban settlements, trade networks, and intra- and interspecific competition is reviewed. Since each rat species is associated with different human societies, they identify unique ecological and historical/cultural conditions that influenced their expansion. Finally, priority research areas including nuclear genome based phylogeographies are identified using archaeological evidence to understand R. norvegicus expansion across China, multi-wave colonization of R. rattus across Europe, and competition between R. rattus and R. norvegicus.

Eric Guiry & Michael Buckley

Abstract

Over the past 1000 years, rats (Rattus spp.) have become one of the most successful and prolific pests in human society. Despite their cosmopolitan distribution across six continents and ubiquity throughout the world's cities, rat urban ecology remains poorly understood. We investigate the role of human foods in brown rat (Rattus norvegicus) diets in urban and rural areas over a 100 year period (ca AD 1790–1890) in Toronto, Canada using stable carbon (δ13C) and nitrogen (δ15N) isotope analyses of archaeological remains. We found that rat diets from urban sites were of higher quality and were more homogeneous and stable over time. By contrast, in rural areas, they show a wide range of dietary niche specializations that directly overlap, and probably competed, with native omnivorous and herbivorous species. These results demonstrate a link between rodent diets and human population density, providing, to our knowledge, the first long-term dietary perspective on the relative value of different types of human settlements as rodent habitat. This study highlights the potential of using the historical and archaeological record to provide a retrospective on the urban ecology of commensal and synanthropic animals that could be useful for improving animal management and conservation strategies in urban areas.

Eric Guiry & Barry Gaulton

Abstract

Rat (Rattus spp.) bone collagen stable isotope values are often assumed to reflect an average of food stuffs that were available to archaeological populations. This paper considers the feasibility of using stable isotope evidence from rat remains as a source of proxy information for human food-related social, economic, and sensorial behaviors. First, a literature review of archaeological and modern ecological rat isotope work reveals that, while rat dietary signatures are often a reasonable proxy for human food waste, they will not always record an unbiased average of foods which are available in a given environment. Second, an overview of ethological, biological, and environmental factors that can influence rat diets is given from the perspective of archaeological bone chemistry, to help identify factors that require explicit and critical consideration when rat stable isotope data is taken as a proxy for human food-related behaviors. Finally, rat stable isotope values are considered to provide new evidence about the social and economic responses of an important historical English fishing community at Ferryland (CgAf-02) to conflict and political turmoil at the turn of the eighteenth century. These results also highlight how information on rat diets can provide a counterpoint to other common faunal isotope approaches that focus on dogs and pigs as a proxy for human dietary behaviors.