These wolves are lit from above by five overhead LEDs, which replaced the original incandescent and fluorescent bulbs. To create the illusion of a moonlit night, the snow underneath the wolves is darkened with paint; this also helps conceal shadows from the hanging lights.
Quinn points out several areas on a massive Alaskan brown bear where its fur has faded. "The fluorescent tubes are high in ultraviolet emissions, which damage pigment," he explains. "The bears have been bombarded [with light] in a fixed position over the years." The animals are cleaned with a mixture of ethanol and water before being touched up with an aniline dye.
The painted landscape behind the grizzlies depicts the Aghileen Pinnacles, a mountain range in Alaska where the animals were caught. "I'm sure many of the glaciers have diminished in size because of climate change," says Quinn.
Before any work can begin on these fragile exhibits, a sculptor on staff builds cantilevered scaffolding to protect the plants and the soil used in the displays. The grass that fills the grizzly habitat, like much of the foreground material, was retrieved on the same Alaskan expedition as the animals themselves in the late 1930s.
jar of oil
Quinn points out a jar of motor oil tucked into the corner of the exhibit, out of view from the public. The substance was left there by diorama artist Raymond De Lucia, with a note on the lid indicating that it should be used to touch up a dark path in the sand. Above the jar, De Lucia and other artists scribbled their names on the wall with dates indicating the last time they entered the scene.
Behind a partition that divides the hall in half---only a few feet from roaring tour groups and squealing kids---Quinn and a team of three artists, three conservators and a taxidermist are at work. Here, Julia Sybalsky, a conservation fellow, is repairing the Canadian lynx scene.
Since visitors can only see one side of the mountain lion's face, conservators have left the hidden half untouched. "Often we will not treat one side [of an animal] to monitor how the pigment will fade over time," says Quinn.
To match the pigments used to color the coats of the display animals, the museum refers to its collection of scientific specimens (kept in dark storage containers), as well as the depictions painted on the dioramas. For example, check out the museum's black-footed ferret: Until it was revamped earlier this year, its coat and raccoonlike eye mask had been bleached nearly white.
One element that has proven difficult to replicate in the displays is snow. Cotton was originally used to pad the Canadian lynx exhibit, but that turned yellow shortly after the hall's opening in 1942. A conservator is the process of testing out synthetic materials, such as chopped polyethylene.
The 69-year-old dioramas that make up the American Museum of Natural History's Hall of North American Mammals are currently undergoing an unprecedented renovation. Generally, the life-size scenes are lightly cleaned every few decades; but this $2.5 million project, which began in January (and has temporarily closed parts of the installation), is a more extensive effort, correcting damage caused by years of bright lighting, temperature fluctuations and dust. The work is scheduled to finish in early 2012, and includes upgrading the glass windows and cleaning the animals themselves. We went behind the scenes with senior program manager Stephen C. Quinn to learn about the inner workings of the exhibit.