In the Field with Carnegie Museum of Natural History

A research museum builds its specimen collections as a public resource.

A Special Research Report by R. Jay Gangewere

The scientific research of Carnegie Museum of Natural History is seen by our readers in limited ways, such as a botanical report on international Trillium research, or an excerpt from a book on the natural history of horses. But the public never sees an overview of a year’s scientific work “in the field,” as they say. There is a good reason for this. Real science is hard to simplify. A scientific paper like Heterochrony and the Evolution of Avian Flightlessness is not easily digested and popularized, nor are references to life zones “20 degrees north of the paleoequator” simply explained.

On the other hand, a selective overview of current museum science is possible, and that is what this report is. Every scientist and every project is not represented (some scientists have a dozen research projects going forward simultaneously). But the more important goal is to share a general sense of the range of the scientific enterprise at Carnegie Museum of Natural History. And this begins with a mission statement:

“Carnegie Museum of Natural History, through its explorations, collections, research, exhibitions and educational programs, advances knowledge of the Earth, its life and cultures, and acts as a steward of our natural world.”

This statement reveals why so much museum-based science is not quickly translated for the public in the exhibition halls, despite its importance for a public interested in biodiversity, conservation and stewardship of the global environment. Most of the research takes place behind the scenes, in collection areas which house over 22 million specimens for scientific study. Likewise, it is not just the work of Carnegie scientists, but springs from the research of a larger family of scientifically curious and motivated people. Scores of knowledgeable Carnegie volunteers add to it, as do scientific colleagues all over the globe at museums, botanical gardens, institutes and universities. Curator John Rawlins says that most of the scientific publications based on the vast collection of insects are written by experts who visit his department to use the collection as a database.

The Moving Targets of Science

At the turn of the century the “Earth” sciences—especially paleontology and the dinosaur collections—made the museum famous. Andrew Carnegie’s money and promotional skills placed the “Home of the Dinosaurs” on the world stage by distributing to capital cities astonishing replicas of the largest fossil dinosaur skeleton ever seen.

Paleontology remains a central focus of the museum, and has great public appeal. But a century later the moving targets of scientific research include a great emphasis on “Life” sciences, which include studies of living mammals, birds, plants, insects, and amphibians and reptiles. Countries all over the world have begun to face the global concerns about preserving the natural environment. And where else but in specimen collections of plants and animals can society turn for valid evidence of the complex web of life, for inventories of life forms past and present, and the biological databases upon which land preservation decisions are made now for the good of the future?

Who could have foreseen that collections of birds’ eggshells by 19th-century Victorian naturalists would prove that 20th- century pesticides have weakened modern eggshells, thus preventing young birds from hatching, leading to the disappearance of bird species? There is a renewed urgency today in the “Life” sciences upon “general field collecting,” or sampling everything that lives in a threatened habitat—all the plants and animals. A museum’s stewardship of the natural world is built upon this global knowledge of biodiversity, and Carnegie Museum of Natural History has been a leader in this fieldwork.

But if anything characterizes museum science in our time it is its interdisciplinary nature, and the subtle ways in which questions about natural history eventually percolate through social, legal and political arenas. One example that surfaced in 1996 is seen in the work of anthropologist James Richardson. Although Anthropology is one of three divisions of research at the museum, equivalent to Earth and Life Sciences as an administrative unit, anthropology frequently requires knowledge of other disciplines. By asking questions about the shellfish found in the ancient kitchen refuse piles of Peruvian coastal villages in South America, Richardson soon found himself a partisan in the debate over the origins of El Niño, the flood and drought catastrophe which overtakes the people of the Andes every seven to 10 years. Thus archaeological digs into 5,000- to 10,000-year-old coastal villages led to thinking about geologic change, marine biology and finally to climatology—in the past and in the present.

El Niño, named by fishermen after the Christ child because it arrives on the west coast of South America during the Christmas season, is the climatic phenomenon that brings massive flooding to northern Peru and southern Ecuador, drought to northern Peru and Bolivia, and is instrumental in disrupting the world’s weather patterns. Analyzing the shellfish and fish remains from coastal Peruvian archaeological sites dating from 10,000 to 4,000 years ago, researchers discovered that a dramatic shift in the species of the marine fauna occurred around 5,000 years ago. This change from warm water to cold water ocean organisms reflected a change in the ocean current patterns along the northern coast of Peru.

In 1996, Richardson, research associate Daniel Sandweiss and an interdisciplinary team of faunal experts, geologists and paleontologists published an article in Science about El Niño. They explained that the evidence strongly suggests that the ocean current circulation pattern before 5,000 years ago was different than it is today.

Before 5,000 years ago the northern coast of Peru received greater rainfall, resulting in more lush conditions compared to the stark desert of that area today. This team states that the change in the ocean currents from warm to cold signaled the origin of the El Niño weather catastrophe about 5,000 years ago.

It has been proposed that the factor bringing about the change was the rising of the Pacific ocean levels by 120 meters. This was because water poured into the world’s ocean’s basins from the rapidly retreating late Pleistocene ice sheets. By 5,000 years ago, modern sea levels were attained and the wide expanse of the world’s exposed continental shelves were submerged by rising seas, resulting in the reorganization of the Pacific ocean current circulation system, bringing on El Niño. Although this hypothesis is controversial, the Peruvian archaeological record of this climate change is now being supported by evidence from Australia.

If the El Niño phenomenon began 5,000 years ago, it is unlikely to disappear soon, and South Americans must adapt to it. Such are the indirect ways in which archaeology leads to predictions about the modern climate.

Life Science—Biodiversity Studies

Life Science at the museum gives insight into many local environmental issues. About 50 miles east of Pittsburgh is Powdermill Nature Reserve, the museum’s 2,000-acre research station in the Laurel Highlands near Ligonier. At Powdermill, a “typical” Appalachian forest ecosystem, the data about animals and plants accumulated since the 1950s provide an essential baseline about species that can be used to monitor the resilience of the entire ecosystem. How does the invasion of a pest species—the gypsy moth, for example—and the human response to it affect the delicate balance of the forest ecology? Should the forest be sprayed to control gypsy moths or not? And with what chemicals?

University scientists in Pennsylvania and West Virginia wrestle with the problem, and at Allegheny National Forest and other regional sites the research on insect species monitors the residual effects of the sprays—the killing of innocent bystander species, so to speak, and effects on the long term “health” of the environment. Carnegie entomologist Robert Davidson has been doing fieldwork and documentation—trapping, preparing, labelling, identifying and reporting—on such species as beetles, caterpillars and silk moths. The jury is still out on the long-term effects of chemical spraying on the forest environment.

Joseph Merritt, a mammalogist at Powdermill, calls small mammals the “key industry” of a forest ecosystem. These animals feed upon plants and in turn are the food supply for many predators that require them for survival. What should be the role of an abundant population of small mammal species in planning for the long-term health of Pennsylvania forests? Should humans not remove dead trees and snags from the forests, if these sites provide essential overwintering nest sites for many mammals and birds?

Merritt’s ongoing small mammal survey employs 250 live-traps to monitor the populations of 13 species of small mammals typical of the forest system, from shrews, moles and mice to gray and flying squirrels. Radio telemetry techniques monitor the behavior of solitary shrews in the winter, for example, demonstrating that these busy creatures have thermal systems and food cache strategies that allow them to stay highly active in the winter, unlike the communal flying squirrels, who “huddle” in group nests to conserve precious body heat. Where else but at Powdermill would scientists demonstrate over a 17-year period that shrews and mice live only about 15 months in the wild, but that some chipmunks live up to eight years?

Powdermill is famous among bird-banders as the largest and longest-standing year-round bird-banding program in North America. Since 1961 the bird-banding program begun by Robert Leberman has monitored the timing of bird migration and the body mass dynamics of different species. Ornithologists from academic institutions around the world use its database of nearly a half-million records.

In 1996 Robert Mulvihill began assessing the possible effects of acid pollution of streams on the breeding densities and nesting success of what may be a “bio-indicator” species—the Louisiana Waterthrush. This species reveals the effects of various kinds of human disturbance to the environment of forested headwaters in the mid-Atlantic region. Another project at Powdermill, the long-term effects of acid drainage from the abandoned Freedline mine, promises more information on the pollution of Appalachian streams, one of the region’s most difficult environmental problems.

Regional research can encompass the entire state, as with Chen Young and David Koenig’s Survey of the Crane Flies of Pennsylvania, a three-year project in collaboration with the Academy of Natural Sciences in Philadelphia and the Pennsylvania Wild Resources Conservation Fund. The end result should be a comprehensive database of crane flies, which is a bioindicator insect for the health of certain ecosystems.

Regional research into mammals progressed in 1996 as Carnegie mammalogists Duane Schlitter and Suzanne McLaren worked with a museum research associate on the first draft of the Mammals of West Virginia, the culmination of seven years of fieldwork. The West Virginia mammal research effort incorporates data from other museums, but the Carnegie collection comprises about one third of the mammal holdings from that state. These studies underscore the long gestation period of museum science as collections develop and are analyzed by many people.

Regional studies are regularly paralleled by international projects. Schlitter, for example, continued work with colleagues on the encyclopedic Rodents of Africa, a work sorely needed by anyone attempting to work with African rodents, which are key agents in the spread of infectious diseases in Africa.

Sometimes international research develops from sudden events. In 1996 Carnegie scientist Ellen Censky, an expert on lizards of the eastern Caribbean, discovered a ready-made opportunity to document the rapid changes in animals as they adapt to their environment or face extinction. Censky observed that Hurricane Luis in 1995 changed the color of two different Caribbean islands. On these islands, each with a barren, blackened limestone surface, several species of dark, patternless lizards evolved—presumably because their color hid them from predators. But the hurricane scoured the islands, removing the dark surface deposits from the rocks and leaving the islands light in color. The dark lizards suddenly stood out, easy victims to predators.

There are few scientifically documented cases of natural selection in action, but this was an opportunity to watch a lizard population evolve in a few generations from dark to light, in order to survive. Birds and other predators will cull the darkest lizards from the population because they are easy to detect, and the lighter-colored lizards will escape, giving rise to a future population light in color. In addition, as the rocks again darken through the years, the population will return to a darker color in order to survive. Censky was funded by the National Geographic Society to monitor the populations.

Isolated populations of island flora and fauna have fascinated scientists since the days of Darwin. Island populations of birds have been a long-term interest of Kenneth Parkes, who published a study of bird species of the Philippine islands in 1991. One of his many current interests is birds of the West Indies, and in distinguishing among the different species of brilliantly colored Stripe-headed Tanagers. This research, including recordings of bird voices, has been done with an international team, which will publish its results in 1997.

Isolated populations for study occur in many habitats. The biodiversity studies in the Amazon basin have received much publicity, but other regions of the neo-tropics also contain them, such as the creatures in the middle and high elevations of the Andes, or the mountaintops of Central America. These have been comparatively overlooked. Tim McCarthy has focused his collecting on diverse species of mammals that live in the “cloud forests” of high elevations of Ecuador, Guatemala and Honduras. The old theory that the general distribution of animals in the lower regions is duplicated in the “island” habitats of the high mountain species is being tested. The conclusions indicate that the genetic isolation of these animals in high elevations makes a difference, and the evolution of such animals remote from their lowland relatives must be understood when drawing a larger picture of mammal evolution.

Entire research collections also come to the museum by purchase or bequest. In the Life sciences entomologist John Rawlins is in the process of acquiring for the museum the second largest scientifically documented collection of fleas in the world— a bequest of the late museum research associate Robert Traub of Maryland. The largest collection is in the British Museum in London. There is no escaping the inherent humor of a flea collection: Do you keep the world’s largest collection of fleas in a matchbox? Can we have our own flea circus? But jokes aside, what about the biological issues? Fleas were the vectors, the transmitting agents for the bubonic plague—the European “Black Death” that killed millions in the 14th century. These tiny parasites sometimes carry disease from one host bird or mammal to another. But which scientifically identified species of flea carries the pathogens from the blood or saliva of one host animal or bird into the bloodstream of another? Questions like this will be answered by using the best and most scientifically documented collection of fleas. Rawlins recently brought one part of this immense flea collection to Pittsburgh in a truck, and there is more to come.

Locally, Carnegie botanists have been working with the flora associated with insect trapping locations in Pennsylvania “barrens” (dry, rocky sites with special vegetation), and at the Allegheny and the Monongahela National Forests. They have documented a number of rare species including a lily newly discovered in Pennsylvania in 1995.

Botanists Frederick Utech and Sue Thompson are also involved in the great Flora of North America project—a multi- volume publication that documents for the first time some 20,000 flowering plants found north of Mexico. Carnegie Museum is part of this multi-national and multi-institutional group undertaking one of the largest biodiversity studies in the world.

Internationally, Utech continued field research with Japanese colleagues on different species of lilies and beech trees common in eastern North America and Japan. Thompson has been documenting the flora of the Caribbean in connection with museum research on insects, and in 1996 collected plants on Puerto Rico in a variety of habitats, including tropical rainforest, serpentine forest, dry forest and mangrove sites. She is coordinating one of the volumes for Flora of the Greater Antilles, another multi-national biodiversity project with the goal of producing a comprehensive treatment of all plant groups on those islands.

Brad Livezey, an expert on birds that do not fly, recently published a chapter in a scientific book on the evolutionary history of “avian flightlessness.” Here is a subject apparently doomed forever to remain behind the scenes—as dead as the Dodo in terms of immediate public concern. The museum exhibits a fascinating model of the Dodo, which was last seen alive in the late 17th century, on the island of Mauritius in the Indian Ocean. The Dodo became extinct because of human influence on the island.

But a museum docent or curator can discuss the topic with modern examples such as penguins and ostriches and swans and chickens and certain kinds of ducks. Why do such birds that we still see today not fly, or fly very little? Flightless birds remain prone to extinction today, and Livezey’s analysis of the evolutionary reasons for flightlessness sheds light on the modern situation. Once the subject is explained,the public begins to understand the multitudinous world of birds that no longer exists, and the reasons for the surviving species of such birds that we do see.

An ornithologist, Livezey is a Life scientist, but his research also depends upon the world of Earth science—the record of past life from fossil remains.

Earth Science—the Fossil Record

Carnegie Museum of Natural History is famous for paleontology—the science of studying the life of past geologic periods from fossil remains. The dinosaur fossils from about 220 million to 65 million years ago are always popular, but lately museum paleontology has also focused on the more recent evolution of early mammals, some 55 million years ago.

Mary Dawson’s research into fossil evidence of small mammals across the northern hemisphere since about 55 million years ago is a good example, and helps establish the evolutionary changes of the Earth. The fossil remains of squirrels, mice, beavers, rats and their relatives are good indicators of these animals’ ancient habitats and environments. The rapid adaptive changes of such animals, their worldwide abundance, and their mobility in diverse habitats, makes them important indicators of Earth history. Dawson’s work verifies the existence of ancient land bridges between Asia and North America, and between North America and western Europe.

Chris Beard, whose discovery of a “missing link” fossil monkey in China won recognition as one of the most important scientific discoveries in 1996, has also been working on early mammal evolution in North America. This year he excavated a “Red Hot locality” in east-central Mississippi. The fossil teeth and bones of about 25 species of mammals found here make it the most diverse fossil assemblage of early mammals in the eastern half of North America. At the site the remains of sharks, skates and rays, bony fishes, snakes, lizards, crocodiles, birds and mammals are intermingled and must be sifted through—perhaps a thousand sharks and bony fish specimens are examined for each mammal discovered.

Hunting fossil bones in the field is backbreaking yet painstaking work. After digging by hand through eight feet of earth on a Mississippi stream bank (the “overburden”), the fieldworker at this site uncovers a fossil-rich sediment which must be washed and passed through a very fine mesh screen, and this strained concentrate of fossil material is then returned to the museum where it is examined under a microscope in the preparation lab.

The bones of these small mammals from Mississippi were apparently concentrated by the weak currents of ancient tidal flows, which were not strong enough to carry heavy bones and teeth very far.

Some of these early Mississippi mammals were squirrel-like or chipmunk-like in appearance, and others resembled shrews or hedgehogs. The early shrews and hedgehogs apparently foraged for insects and prey on the forest floor, while in the treetops different kinds of small primates scampered. Two different kinds of opossums ranged on both the ground and in the trees, and an otter-like animal spent much of its time swimming in swamps and channels, foraging for small fish and mollusks. This was also the era of the “dawn horse”—the primitive ancestor of the modern horse, and of small hippo-like animals called pantodonts. Early carnivores, primitive relatives of dogs and cats, hunted the small rodents and other vertebrates.

Beard draws some conclusions about the biotic zone which stretched across part of North America: “Overall, our research shows that the mammals that inhabited the Gulf Coastal region of the southeastern United States were not vastly different from those that inhabited the Rocky Mountain region at the same time. Although the Red Hot locality only samples one brief episode during millions of years that comprise the early part of the Age of Mammals, it is reassuring as a paleontologist to see that the fantastic fossil record we have uncovered in the Rocky Mountains for more than a century may not be such a biased picture of North American mammals after all.”

Alan Tabrum is also collecting the fossil evidence of extinct mammal life from some 40 million years ago, collected in areas such as southwestern Montana and Utah. In this period important animal groups, such as true rhinoceroses, first immigrated to North America.

The adaptation of some mammals from land to life in the sea is the subject of Zhexi Luo, an expert on the origin and early evolution of whales. In the last century creationists argued that Darwinians could not demonstrate the missing links between early life and human beings, but modern research continues to establish the links between sea and land creatures. In Luo’s research, the evolution of cow and pig-like animals into whales and dolphins—our modern marine mammals—is being demonstrated. His study of the skulls of fossil whale species demonstrates the adaptive process by which the organs for hearing, for example, changed so that mammals could hear sounds underwater.

The oldest fossil material collected recently by Carnegie scientists dates from about 325 million years ago, when much of North America was covered by a shallow sea. This sea was bounded in the central and southwestern United States by thick reefs rich in marine life, and John Carter is studying limestone accumulations which contain exquisitely preserved shells. The site was discovered during a road excavation in northeastern Oklahoma.

Likewise, paleontologist Albert Kollar is documenting the life of the same ancient seaways which covered North America, and he and assistant Ilona Weyers recently discovered unusually large specimens in southeast Alaska. Called Gigantoproductus, these specimens are of a rare clam-like animal from North America, and possibly a new species.

David Berman has been collecting the fossil remains of animals from 310 to 230 million years ago, when the land masses of the Earth were united in a single continuous supercontinent, referred to as Pangaea. His excavations with colleagues in both Germany and the United States reveal the presence of shared life forms across a narrow band of terrestrial life around the Earth—about 20 degrees north of the paleoequator across the southern region of Euroamerica, where a warm, humid, tropical climate once existed.

Amy Henrici, who prepares scientific specimens in the museum laboratory, is studying the evolution and diversity of frogs through time. One of her projects is to identify a new genus and species from Dinosaur National Monument, a fossil creature whose modern relatives include the Mexican burrowing toad and the African clawed frog. For the public, watching a preparator like Henrici carefully removing fossil bones with dental tools from the hardened “matrix” which preserved them is a highlight of any behind-the-scenes visit to the museum.


Collecting artifacts from past human cultures has never been simple. A century ago when Carnegie Institute opened its doors, President William Frew wrote a personal letter to the great scout William F. Cody, asking him if he could collect artifacts from the Plains Indians for the new Pittsburgh museum. Buffalo Bill replied, “the kind of articles you mention are very scarse,” and that “The uncivilized wear what the government gives them. The buffalo and deer are gone and they live no longer by the chase. I would not know where to buy such things as you want.”

But after a century of collecting, the museum does have an important collection from prehistoric and historic cultures. The opening of Alcoa Hall of Native Americans in 1998 will display Native American materials according to the latest state of scientific knowledge. Marsha Bol, an expert on Indian cultures of the American plains, has overseen the development of the hall.

In Pittsburgh, Carnegie scientists have proven themselves for decades as leaders in urban archaeology and regional history. In 1996 Upper Ohio Valley archaeological research continued with excavations at sites in Washington County, where Richard George recorded two settlements in the ongoing effort to refine the chronological history of the Monongahela people. Similarly, Stanley Lantz documented Proto-Iroquois settlements in northwestern Pennsylvania and southwestern New York, and Verna Cowin documented artifacts from Lawrence County historic cemetery sites, and Native American burial mounds from A.D. 530 to 850.

But today field archaeology has a totally different context than it did when anyone could write Buffalo Bill about obtaining collectible objects. On an international level archaeology can be an exercise in international relations, as well as a cooperative venture among scientists and ordinary people. In addition, archaeologists are now engaged to undertake the historic preservation research that accompanies new construction on undisturbed land and even urban sites. In the United States government regulations frequently require that a small percentage of the site preparation costs be spent on salvaging historic materials that would otherwise be lost. Also, historic artifacts are no longer easily sent to other countries, since many nations now care about documenting their own cultural history, and see scientifically validated material as important.

Research in the Caribbean by anthropologist David Watters reveals such current themes. Several years ago Watters collaborated in an archaeological dig with Cuban colleagues, as part of the first American-Cuban team in many years to explore a Cuban site. In 1996 his expertise in Caribbean archaeology led to another experience.

On July 18, 1995, the Soufriere Hills volcano, which had been dormant for hundreds of years, exploded on the small island of Montserrat in the British West Indies. Just three weeks earlier anthropologists Watters and research associate James Peterson from the University of Maine, Farmington, had completed an archaeological dig sponsored by the Montserrat National Trust. They excavated pottery and other artifacts from sites occupied by the Saladoid people for 800 years, from 500 A.D. 300. The site was being prepared for a new airport on the small island, which occupies only 39 square miles. Evidence of the early inhabitants was being prepared for the local museum, and the museum is one of the features of the island for tourists.

The disastrous eruption began suddenly and without warning, venting clouds of steam and ashes skyward, and unleashing fast moving flows of ash, rock and magma down the east side of the mountain into the sparsely inhabited Tar River valley. On the west side of the mountain the populous capital of Plymouth received huge billowing clouds of ash blown westward by prevailing winds. The volcanic activity continued for a year and a half, prompting the government to evacuate people living in Plymouth and the southern third of the island to a “safe zone” further north.

The island’s museum in Plymouth was closed, as was the storage facility with the many artifacts excavated by the archaeologists, who had shipped to the United States only those objects requiring further laboratory study not possible on the island. In 1996 Watters and Peterson returned to the island to study, reinventory, and repack the artifacts in storage containers Watters had shipped from the United States. At one point they were enveloped in a huge ash cloud from the active volcano as they worked, protected by dust masks and goggles. They helped their Montserratian friends sweep piles of ash from decks, porches and roofs, and when the rains came, shovel the stuff away. Once hardened by water, the powdery ash turns concrete-like. But through it all the artifacts were saved, and will someday contribute to the way that the people of Montserrat present their history to the world.

Another example of international research is the work of Sandra Olsen in Kazakstan, central Asia. Her focus is on evidence of the early domestication of the horse, and the central steppes of Asia are a logical place to look for the evidence of the way nomadic peoples first tamed horses. The museum has been collaborating with North Kazakstan University at the site of ancient Botai, where between 3600 and 2600 B.C. on the west Siberian plain people subsisted almost entirely on horse meat.

The early tools found suggest the making of thongs that might have been used to control horses, and to make whips, riding crops, bridles, hobbles, lassos and pole snares. The hunters used the bow and arrow, spears and harpoons. Anthropologists know that saddles were invented much later. This early people and their animals adapted to an extremely harsh climate, where there is poor soil, low rainfall, and winters with temperatures below -30 Celsius. Other information gleaned from excavations include cloth weaving preserved in impressions in pottery clay, and proof of using human skulls in a ritual manner by removing all the skin, drilling holes in the top for suspension, and covering the face with clay.

At another site in southwest France called the Grotte des Eyzies, Olsen has been concluding work on a Paleolithic rockshelter site (10,500 B.C.) from which material was taken to the British Museum in 1860. Evidence of the early hunting techniques indicate that the people subsisted largely on reindeer, brought down with harpoons and spears. Some of the earliest evidence of air-drying or smoking meat to preserve it comes from this site. Drying meat, like beef jerky, reduces it to one-fifth of its fresh weight and makes it easy to transport, an important consideration for nomadic hunters.

The international sites worked by Carnegie anthropologists, like Richardson in the coastal villages of Peru, Watters in Montserrat, and Olsen in Kazakstan, are a sign of the collaboration called for in our times.

After Andrew Carnegie’s support a century ago, innumerable foundations, agencies and benefactors have made Carnegie Museum of Natural History a world-renowned research museum. But the great specimen collections must be seen also as the result of a century of work by dedicated researchers who go “into the field” on behalf of science.

R. Jay Gangewere is the editor of Carnegie Magazine.