Exploring the Enormous Collection: 11 Million Preserved Specimens in the Field Museum's Basement

From Bonnethead sharks to bigel Komodo dragons, the Field Museum in Chicago houses an impressive collection of over 11 million fluid-preserved specimens in its basement. Among these specimens are 883 frogs, each carefully preserved in jars filled with fluid. The question arises: why hold onto these specimens, and why keep them wet? The answer lies in viewing the collection as a living library, where each jar serves as a book that researchers can open to study the diverse species, shapes, and, in some cases, DNA. Essentially, it allows scientists to maintain a quasi-live zoo within their laboratories.

Acquiring and preserving these specimens is no simple task, especially when dealing with large and complex animals like Komodo dragons. The Field Museum obtains its specimens through donations or strategic euthanization in the field. For example, common water snakes are euthanized for research purposes, and extracting valuable DNA from them is a crucial step in the preservation process.

Sarah, a researcher at the Field Museum, emphasizes the significance of DNA collection, a relatively recent addition to the preservation process. Using scissors and forceps, she carefully extracts DNA from the inside of the snake, taking precautions to ensure the sample's purity. The collected DNA is then stored in massive liquid nitrogen freezers alongside thousands of other samples.

The preservation process involves various steps, including formalin treatment to keep the specimen frozen in time. Sarah takes into consideration the information needed for current and future research, such as the specimen's sex. For instance, she ensures that the sex of a snake is discernible without opening the jar, showcasing the meticulous care involved in this scientific endeavor.

The next step in preservation involves alcohol baths, a less toxic alternative to formalin for long-term storage. Alcohol preserves the specimens without significant changes and is safer for researchers. The final resting tanks maintain the specimens' lifelike appearance, with larger specimens occasionally releasing debris and oils that can cause discoloration but do not compromise preservation.

While most specimens are kept in their natural form, others undergo a unique process. Small fish with intricate skeletons are dyed blue, then treated with an enzyme called trypsin to make them transparent. Finally, the bones are dyed red, resulting in translucent specimens that can be studied under a microscope alongside the opaque ones.

The wet collection, resembling a vast library of life forms, holds surprises for researchers. Some specimens remain untouched for years, hidden on the shelves until a curious person cracks open a jar. This curiosity has led to the discovery of entirely new species, as exemplified by a spider-tailed horned viper that remained misidentified for decades until herpetologists unveiled its true nature.

Maintaining this extensive collection comes with challenges, such as organizing and cataloging each specimen. With distinct identification numbers and a meticulous categorization system, researchers navigate the shelves to locate specific specimens. Even though space constraints have led to combining jars, each specimen remains invaluable, and the option of discarding them is unthinkable.

Old specimens, like the oldest one in the amphibian and reptile collection, present additional challenges. Extracting DNA from century-old specimens involves a complex process with varying success rates. Despite the challenges, the effort is worthwhile, as every specimen, regardless of age, contributes to the ongoing quest for scientific knowledge.

In conclusion, the wet collection at the Field Museum serves as a remarkable testament to biodiversity, offering researchers a unique opportunity to study the past and present of various species. This living library, with its meticulously preserved specimens, continues to shape our understanding of the natural world, ensuring that the legacy of each organism lives on in the pursuit of scientific discovery.