| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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| Here At the Academy All Skin and Bones In a little shed on the California Academy of Sciences’ rooftop, Lise Thomsen inserts the tip of a scalpel into the flesh of a dead sea otter. Starting near the sternum, she slices down the length of its body and, with one smooth motion, cleanly peels off the animal’s skin. Surrounding the skinning table are counters covered with bones: gray fox bones, monkey hand bones, bones from porcupines, porpoises, and delicate passerines. Today, a half dozen sea lion skulls stare vacantly toward the dissecting table, where they too once lay within a decomposing carcass. Tomorrow, they may be gone, a killer whale skull in their place. For more than 30 years, Thomsen, the skin and bone preparator for the Academy’s Birds and Mammals department, has transformed washed-up, run-over, and dropped-dead animals into smooth study skins and squeaky clean skeletons. At times her job can be messy, but her products are works of art that form the backbone of the department’s research collection. Today that collection boasts more than 100,000 birds and over 30,000 mammals. Thomsen speaks softly but with matter-of-fact bluntness. Unless she’s pausing to talk about how her current subject hunted, or flew, or what it ate before it died, she seems to be always driving forward. “The name of the game is ‘don’t waste any time here,’” she says.It’s easy to see why: the quantity of animals she processes is bone-chilling. The department receives over a hundred accessions—an accession can be a single robin or a bag of 60—each year. Since Thomsen arrived in 1971, the department has prepared nearly 3,500 accessions. And there are always more coming in. “We’re up to our eyeballs with things,” Thomsen says. So dead animals pile up in the commercial-sized freezer: parrots, geese, whale heads, even parts of San Francisco Zoo’s Sumatran tiger Benjai, which died in April. A bag of frozen quail doves will be parasite-free skins next week; another bag of doves will be skeletons. “We’re working at about optimum capacity,” Thomsen says. “When you try to stuff 20 things through, it creates a lump in the pipeline, and you have difficulty at all stages because there’s not enough storage space, there’s not enough buckets.” Preparing a skin or a bone isn’t as cut and dry as it might seem. First, Thomsen records vital information, such as the specimen’s weight, size, and where it was found. Then comes the cutting and drying. After she’s relieved the body of its former covering, Thomsen opens the body cavity, determines the sex of the animal, and “takes a couple snippets” of muscle or other tissue for the Academy’s frozen collection—a storehouse of material for genetic studies. If the remaining shapeless tangle of feathers or fur is in good condition, she reshapes the skin into its original form, stuffing it with cotton and sometimes support wire. If it’s a bird, she wraps it like a mummy in sheet cotton. “If you don’t,” says Thomsen, “you’re in deep trouble. Whatever position you set them in is going to change as the feathers dry and the skin dries a little bit.” The specimen finishes curing in a wire mesh enclosure that lets in plenty of air but keeps out flies, and then it’s ready for the collection. Bones require a little more elbow grease. First, Thomsen tears off the meat. “You remove most of the muscle with knives and forks and spoons and time,” Thomsen says. What remains goes into the “bug case,” a galvanized metal vault housing drawers of ravenous carrion beetles. The thousands of beetles can reduce a seal carcass to a skeleton in a week. In between specimens, Thomsen sometimes feeds them “treats” such as pig’s trotters to keep them healthy and mating. Once the beetles finish feasting, the nearly clean bones are soaked in water, then bleach—a dark or blotchy bone may hide revealing features—then ammonium, and finally solvent to remove any leftover grease. According to Thomsen, degreasing is the most important step in the process. The fats oxidize and turn acidic over time, so if they’re not removed, the bones will eventually disintegrate. The whole preparation process—from rotting flesh to spot-free skeleton—can take one day or several months, depending on the size of the specimen. The gruesome details of her work leave Thomsen unfazed. “It’s not gross,” she says, working with a dead animal. “It’s interesting.” And it’s important. Scientists the world over scrutinize the bones and skins Thompsen prepares. Biologists might be looking for evolutionary relationships between species, or the molting patterns of birds; archaeologists who find bones in middens use the collection to identify what species Native Americans were eating. Artists illustrating field guides sometimes come to the collection for a close-up look at pelts and feathers. All told, the collection attracts more than 2,000 visitors each year. Thomsen has shared her workspace with thousands of animals over the years, including a manatee named Buttercup, a late and beloved resident of the Academy that died in 1984. But, Thomsen says, her job isn’t all about the numbers of bones and skins she can produce. It’s about quality. “Why put in all this effort if you don’t do it really well?” she asks. “You never know who’s going to come through the door, and that’s just the thing they want.” Dave Brian Butvill is associate editor of California Wild. |
Summer 2001
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