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In 2005, a mother and two baby rats were discovered in Salt Lake City onboard a truckload of sterile medical supplies shipped from China. The mother was destroyed, but the babies were kept. The rats were sent to Dr. Michael Mares, the Sam Noble Museum’s Director and a noted mammalogist, for identification. However, a rather puzzling DNA analysis was conducted at Oklahoma State University. Although the mother looked like a common ship rat, DNA suggested she was not a pure ship rat. Dr. Mares teamed up with genetics graduate student Dr. Justin Lack of Oklahoma State University in a pursuit that would eventually yield novel discoveries for invasion biology.
“In our efforts to learn more about Rattus in the United States, the project eventually grew into Lack’s dissertation, which is a fine piece of work involving both the ship rat and the Norway rat, two of the most destructive invaders in the world,” recalls Dr. Mares.
Along with Dr. Ron Van Den Bussche and Dr. Meredith Hamilton of OSU and Dr. Janet Braun of the Sam Noble Museum, they began researching the invasion history of various Rattus species using population genetics, a method of research in which the geographic patterns of genetic diversity are analyzed to understand gene flow and evolutionary history. During the study, the group encountered a third species, Rattus tanezumi, capable of hybridizing with the ship rat (Rattus rattus). For photographs of these species, click here.
Although a population of Rattus tanezumi had been described from California, Dr. Lack and his colleagues were the first to report the second and only other known population in Florida. This discovery suggests Rattus tanezumi likely invaded the United States twice, once on each coast. Globalization in means of transport (ships, trucks and planes) enabled the hybridization. Unlike the hybridization of various dog breeds, which are considered to be the same species, Rattus tanezumi contains genomic material from Rattus rattus (a separate species) and may become genetically swamped by the more widespread and aggressive species.
“Genomic swamping like this is very rare in mammals, making this a really cool result,” said Dr. Lack. “However, a major consequence has been the potential loss of the R. tanezumi nuclear genome.”
To better understand the invasion origins of the Norway and ship rat, Dr. Lack and his colleagues conducted a second study that provided insight into dispersal patterns. They found that the Norway rat invaded from at least four sources, most likely two from Asia and two from Europe and/or Africa, whereas the ship rat appears to have entered the United States in a single wave of invasion, with subsequent invasions only occurring in southeastern Florida but never moving inland.
Their work showed that the Norway rat, Rattus norvegicus, continues to move throughout the United States, whereas the ship rat, Rattus rattus, no longer continues to disperse or enter. Analyses suggest that competition with the more aggressive Norway rat may limit the success of the ship rat. Through this study, researchers gained insight into how these species disperse and repopulate outside species lines. They are two of the principal pest species in the United States and can have great adverse effects on human health by acting as reservoirs and dispersers for a variety of diseases, from bubonic plague to typhus and leptospirosis. This work on dispersal patterns can be useful in limiting the spread of the rat-borne pathogens.
Orphaned collections are a growing concern for natural history institutions worldwide. An endangered or orphaned collection is any considerable body of material, which is or soon may be no longer regarded as of value in its present ownership. According to the American Association of Museums, every year more institutions, agencies, corporations, and individuals divest themselves of their collections. When this occurs, “orphaned” collections need to be “adopted” by an existing natural history collection.
In November of 2011, Eugene Young, a professor in the Agriculture and Life Sciences department at Northern Oklahoma College in Tonkawa, Okla. contacted the Sam Noble Museum about the possibility of adopting an orphaned collection from the A.D. Buck Museum.
Originally called the Yellow Bull Museum, the A.D. Buck Museum’s science exhibits included mounted specimens of birds and mammals. Sam Noble Museum curator Gary Schnell and collection managers Marcia Revelez and Tamaki Yuri traveled to the A.D. Buck Museum to view the specimens. Upon further inspection, the team found many specimens that had been on loan from the Sam Noble Museum.
A total of 14 specimens were loaned to A. D. Buck in 1961, including an adult grizzly bear, all still in good condition. Most of the collection’s Oklahoma birds and mammals were found in the early 1900s, such as the marsh hawk, in 1910, and a Pintail, in 1913.
Many of the specimens in the A. D. Buck collection are significant to Oklahoma’s history, such as the Spotted Skunk found in 1934 in Kay County, an area that had no previous record of having that species before the 1990s. After evaluation, a crew returned in December to pack up the collection of birds and mammals and bring them to their new home at the Sam Noble Museum.
The A. D. Buck specimens are not the first collection the museum has adopted. Recently, the museum’s Department of Mammalogy adopted approximately 26,000 mammal species from the University of Memphis Mammal Collection.
“It’s an ongoing goal for the museum to aid orphaned collections,” Revelez said.
Natural history collections play a vital role in understanding cultures, habitats, biodiversity and more. They safeguard specimens, inspire, educate, and tirelessly continue the research and study of various sciences. We welcome back our mammals and birds that have been on loan for so many decades and will always strive to maintain and preserve Oklahoma’s rich natural history.