To celebrate Squirrel Week, the Torch is revisiting a chat we had with the Smithsonian’s resident squirrel expert, Richard Thorington.
As a boy, Richard Thorington was intrigued by the ubiquitous squirrels he saw in his backyard. He had a lot of questions. “Why do so many squirrels get hit by cars? Why are some squirrels black? Do squirrels fight with each other? How can I keep them from raiding my bird feeder?”
Almost 40 years later, Thorington, curator of mammals in the Vertebrate Zoology Department of the Natural History Museum, still has questions, but he also has many of the answers in his book, Squirrels: The Animal Answer Guide, from Johns Hopkins University Press.
Co-authored by Thorington’s longtime research assistant, Katie Ferrell, the book offers detailed answers to these and many other questions about squirrels. For example, the so-called “black squirrels” seen in the eastern United States are simply common eastern gray squirrels with more melanin.
And, yes, squirrels do fight—to establish dominance and to defend their territory, mates and young. The sad reality of squirrel deaths on roadways is primarily due to the bushytails’ predator-evasion tactics. Squirrels dart this way and that like a champion running back bound for the end zone to dodge the jaws and claws of dogs, cats and foxes. This technique is ineffective against a speeding car, however, and dodge versus Dodge often ends badly.
Squirrels covers the expected—squirrel genetics, socialization, reproduction, feeding and ecology. It also delves into less often considered subjects, such as how these animals figure into literature and mythology, squirrel problems (from a human viewpoint) and human problems (from a squirrel’s viewpoint).
Throughout the book, Thorington and Ferrell tap the expert knowledge of many scientists from across the globe. “Our purpose in writing the book was to cover the whole world of squirrels,” Thorington says. “It’s the outcome of a naturalist’s basic curiosity.…It’s gratifying for me that several of my colleagues have been able to use information from the book in their own lectures.”
Thorington began his career at the New England Regional Primate Research Center at Harvard before coming to the Smithsonian. He continued to work on primate research during the 1970s and early 1980s at the Smithsonian Tropical Research Institute’s Barro Colorado Island facility in Panama and elsewhere. He also conducted studies of tropical squirrels during that time. In Squirrels, Thorington describes the wide range and variety of the Sciuridae family of rodents whose common ancestor lived some 30 million to 40 million years ago. That ancestor gave rise to the 278 species of squirrels known to exist today, ranging from the magnificent giant tree squirrels of Southeast Asia to the tiny pygmy squirrels of Africa. The pygmy squirrel weighs about half an ounce, while its giant counterpart can weigh as much as 4 to 6 pounds.
Generally, squirrels are divided into three main categories: tree squirrels, flying squirrels and ground squirrels. The largest ground squirrels, marmots, weigh as much as 18 pounds. I was particularly interested in describing the diversity of squirrels, which is generally underappreciated,” Thorington says. “One of the things that surprises me is that a lot of people don’t realize chipmunks and woodchucks are squirrels.”
One of Thorington’s major achievements in squirrel research is his now-accepted theory that flying squirrels evolved separately and the different species of flying squirrels are more closely related to each other than they are to other squirrel species.
Thorington has conducted research in India and Southeast Asiaand across North America, among other points on the globe. But fieldwork became increasingly problematic as a progressive nerve disease gradually made Thorington quadriplegic. “As navigating rough terrain became more difficult,” he says, “I began to emphasize museum studies of systematics and anatomy, with more of an emphasis on squirrels.” Many of the observations and photography included in Squirrels were made right from Thorington’s own kitchen window. Among the images his wife, Caroline Thorington, provided for the book, is a photograph of the nocturnal Southern flying squirrel feeding at the Thoringtons’ kitchen-window bird feeder.
Obviously, despite years of research, the answer to the age-old question of how to keep the dauntless squirrels off a bird feeder remains elusive.
Posted: 8 April 2013