Written by Sheila Mcclure

Specimens are important for our ongoing study of the Earth's environment and biodiversity. Blueprint Earth volunteer Sheila McClure gives us a step-by-step view on the process.

A museum research specimen of a mammal usually consists of a study skin (filled with cotton) and a cleaned skull. The skin is removed from the specimen, treated with absorbents and filled with cotton. Wires or wooden dowels are used to support the legs and tails of the specimen.

I was fortunate enough to be selected to prepare a museum specimen of a gray fox (Urocyon cinereoargenteus) as a project for a mammalogy class. Prior to this, I had only prepared a mouse specimen. There are specific protocols to follow to ensure successful specimen.

My fox had been hit by a car and found by a biologist, who carefully preserved the carcass in the freezer, noting the exact location and circumstances under which it was found.

A fox takes some time to thaw, due to its well-insulated pelt, which I had not anticipated. Gasoline and a toothbrush were used to clean the small amount of blood from its fur. The fox was weighed, sexed and measured, including her total length, tail, hind foot, and ear lengths.

Once the tasks of dealing with the external part of the specimen had been accomplished, I began to remove her pelt, eventually stuffing it with cotton and wires. This had to be done very carefully so the pelt could be retained as close as possible to its original condition.

Starting with an incision just above the urogenital area to an area near the forelimbs, I worked the skin off of the limbs and body and eventually the tail. It was difficult to remove the skin from the head and ears, but with perseverance, I was successful. The pads of the fox's feet were injected with formaldehyde as a preservative to maintain a lifelike appearance. Upon completion of stuffing with cotton, wires, and dowels, I stitched up her ventral incision, placed her on a board and pinned her limbs and ears in a standard position. Museum specimens are made rather flat to fit in a drawer.

Lastly, I brushed her fur and left the skin to dry.

Specimen preparation is somewhat of an art and working on this project gave me an appreciation for all the specimens in the museum that are so neatly stuffed and sewn together that they almost appear life-like.

With biodiversity declining around the world, properly prepared and cared for specimens are becoming increasingly valuable. As species become scarce, studying them becomes more difficult.

Natural history collections provide samples of species that may otherwise be unobtainable. Data gathered from prepared skins may provide insight into why a species is in decline in the wild, as well as how individuals vary over time and space.

 

 

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