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Dr. Ross D. E. MacPhee, Curator in the Division of Vertebrate Zoology at the American Museum of Natural History Jeff Saunders © AMNH |
Bio Dr. Ross D. E. MacPhee is a curator in the Division of Vertebrate Zoology at the American Museum of Natural History. Dr. MacPhee's work focuses on extinction, in particular the extinction of mammalian species allegedly caused, or indirectly accelerated, by human behavior within the last 40,000 years. Most recently, Ross' work has revolved around the possibility that the extinction of large mammals at the end of the Pleistocene Epoch (approximately 11,000 years ago) was caused by diseases introduced through contact with humans or their commensals, the organisms that depend on them or interact with them. |
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When Ross began his undergraduate degree in history at the University
of British Columbia, Canada, he never intended to study science.
His passion at the time was directed towards the study of human history
and his focus was the history of sub-Saharan Africa. However, all
students in the humanities were required to take a science course to
graduate. Because he felt he had no affinity for science, Ross elected
to take a course in physical anthropology, which he imagined to be less
scientifically rigorous than, say, a course in either chemistry or
physics. Much to his surprise, Ross soon found that he was engrossed in
the subject of physical anthropology, particularly in the areas of
morphology, evolution, and fossils.
Ross excelled in his physical anthropology class. As a result, the professor, an archaeologist, invited him to work with him on an archaeological dig during the summer break. This gave Ross his initial experience of fieldwork. And for the first time he encountered the subject of Pleistocene extinctions. His professor's research was concerned with the early human presence in North America. It involved trips to cave sites to look for evidence. These sites also contained remains of extinct mammal species. The largest North American mammals in existence today are bison and bears. Both animals are relatively small compared to animals like the mammoths and giant sloths that lived at the same time as the earliest known North American humans. Ross started to develop a research interest in possible reasons behind the subsequent extinction of these megafauna. In graduate school, Ross carried out field research in eastern Nevada. There he was astonished to find an abundance of fossilized remains of such animals as American horses, huge condor-like birds, camels, and sloths. Fascinated that these animals could have survived in the rough country of eastern Nevada, Ross started to imagine how different the landscape must have been when these animals were alive. A passion for studying the causes of extinction of these early mammals took root. Ross graduated with a Ph.D. in Physical Anthropology from the University of Alberta, Canada, in 1977. In 1981 he took up a teaching position at Duke University and continued his research. He became a curator at the Museum in 1988. In addition, he is an adjunct senior scientist in the CERC program at Columbia University and an associate professor at the State University of New York at Stonybrook, New York. Ross is currently series editor of Advances in Vertebrate Paleobiology, a continuing series of books on different subject areas in paleontology. |
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Work Inspired by his initial fieldwork experience as a college freshman, Ross continues to research the causes of megafauna extinctions at the end of the Pleistocene Epoch. The two popular and accepted hypotheses for the causes of Pleistocene extinctions - overhunting by humans or reaction to sudden and extreme climate change - failed to fully convince him. |
Dr. Ross D. E. MacPhee holds a mammoth tusk in the AMNH fossil collection. Tina Gaud © AMNH | He proposed the hypothesis that the first peoples that entered the Americas inadvertently imported pathogens that the native species had no immunity against. These pathogens managed to infect new hosts, thereby causing terrible plagues and enormous mortality. According to his argument, in many cases the mortality was so great that extinction ensued. Ross refers to such newly emergent diseases as "hyperdiseases." What made them so dangerous was that the species of the New World had no defenses against them. |
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How did he come up with this idea? In 1994, Ross read an article about
the Ebola virus in the New Yorker magazine. He was intrigued by the idea
that "new" diseases can strike (or "emerge") in new human hosts all the
time. The pathogens that cause newly emergent diseases in us, like Ebola,
are not necessarily new in an evolutionary sense; they could have existed
for hundreds of thousands of years in their original animal hosts. However,
conditions may change - as they do, for example, when humans clear out huge
tracts of rain forest, exposing themselves to animals and diseases they
had no previous contact with.
Ross then wondered if an emerging disease could have been the source of the mammoths' demise. As you will learn in the course, Ross and Alex Greenwood and their collaborators are trying to test this idea. Ross has also long been interested in historical biogeography, or the geographical distribution of different species over time. This area of his research focuses in particular on the colonization of islands, specifically the Greater Antilles, by mammal species: How did mammals that live on islands, such as primates, sloths, and marsupials, get there in the first place? No mean feat when you consider the fact that these islands are separated from the mainland by hundreds of kilometers of water. In the case of the Greater Antilles, Ross hypothesizes that mammals were able to colonize these islands because they once formed part of a land span that connected North and South America. He has been successful in finding appropriate fossils that provide the evidence he needs to support this hypothesis. |
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Research Ross enjoys the challenges of fieldwork which appeals to his practical manner and solution-oriented bent. His research takes him to different countries, often to remote locations, and always with a team of people. |
| There are matters of budget and time constraints to consider. Each country has its own laws about collecting, which must be researched in advance, and all necessary permits and visas have to be acquired in advance of the trip. Setting up these trips and figuring out all the logistical arrangements take specific skills and intricate planning. Ross is forced to rely heavily on his wits in order to ensure that the field trip runs smoothly and efficiently. | 
Wrangel Island, Siberia - one of the islands where Dr. MacPhee conducts field research - contains an abundance of mammoth fossils. Here, Dr. MacPhee holds a mammoth tusk that he collected in 1998. Clare Flemming © AMNH |
| His modus operandi remains the same, no matter what his research topic. When he remains unconvinced by conventional explanations to a situation, Ross develops a theory that at first might seem implausible, like the hyperdisease hypothesis. Ross believes you must continually question and challenge existing explanations of phenomena and consider ways to test them, or make them more understandable. He believes that when you do so, you often find that the received wisdom turns out to be based on shifting sands. His goal is to come up with an explanation that is not only more comprehensive, but also more testable. To Ross, this is what science is all about. |
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Bibliography
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MacPhee, R. D. E., and D. A. Burney, "Dating of modified femora
of extinct dwarf Hippopotamus from southern Madagascar: implications
for constraining human colonization and vertebrate extinction events."
Journal of Archaeological Science, 18: 695-706. 1991.
© 2000 American Museum of Natural History