OLD-FIELD MICE HAVE ESCAPE TUNNELS

by Whit Gibbons

November 26, 2017

We were standing in a field of recently planted longleaf pine trees when I handed my grandson Nick the shovel and said, “Dig right there where the hole is.” He did so, and a minute later, out of the ground popped three little mice, scampering away into the underbrush. “How did you know they would be there?” I answered, “Mike Smith, taught me how to find them.”

I have dedicated columns to other well-known biologists such as Eugene Odum and Joab Thomas who influenced my career as well as the profession itself. Michael H. Smith, who died on November 15, 2017, at the age of 79 fits into this category--another loss to the field of ecology, as well as my loss of a longtime friend and colleague. Prior to becoming a professor at the University of Georgia, Mike did his doctoral dissertation research on the biology of these fascinating little mice at the University of Florida. He passed some of what he had learned on to me when he and I were young faculty members together in the 1960s.

Nick and I only dug up one burrow. Our intent was not to destroy an animal’s home but to confirm that the mouse-size holes with a little apron of sand outside belonged to a native mammal, the old-field mouse. These are not mice you would ever see in a house. They are wild ones that live in fields and on beaches. As Nick dug, the mice burst out of sandy soil a few feet away from where the hole was. As Mike discovered while he was a student, they do this via an escape tunnel they dig upward from the underground burrow. The escape route has no opening to the outside but ends an inch or so beneath the surface, allowing them to quickly push their way out if a snake enters the burrow looking for a meal. No babies were in the burrow cavity, so all the little sand diggers were old enough to create new burrows nearby.

Many ecologists concentrate on specific groups of plants or animals. Mike Smith was a mammalogist, as well as an accomplished geneticist and an expert on radiation ecology. He was internationally known as one of the first ecologists to investigate the effects of radiation on the ecosystems surrounding Chernobyl after the nuclear reactor accident. In an earlier study, he compared the levels of radiocesium in deer from the Department of Energy’s Savannah River Site with deer taken from other areas in the region. Radioactive cesium, a common by-product of nuclear reactors, has been measured in deer in many parts of the Southeast since the 1960s. The cesium counts from deer at all research sites were essentially the same and consistently low. One of his conclusions was that the primary source of measurable cesium in deer and other wildlife on the SRS was from fallout that occurred during Cold War atmospheric bomb testing, not from the nuclear facility.

Mike’s research was exemplary, but much of his claim to ecological fame came from being director of the University of Georgia's Savannah River Ecology Laboratory for a quarter of a century. Under his leadership, SREL not only was cited by the Guinness Book of World Records for some of its classic research but was also recognized as a premier ecological laboratory in a worldwide review of scientific institutions by Encyclopedia Britannica. Mike’s administrative guidance, his mentoring of new students and faculty and his own research led to SREL’s success and recognition. He demonstrated how a professor of ecology could simultaneously conduct ground-breaking research and manage a preeminent scientific laboratory.

Mike Smith left many legacies beyond his research and the development of what arguably became the best-known field ecology laboratory in the world. I appreciate them all. But I particularly appreciated being able to show my grandson how to find old-field mice because Mike Smith had once showed me.

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