The Canadian Museum of Nature’s collection is filled with irreplaceable natural history specimens. We ensure each specimen is protected in a stable environment to prevent degradation over time. But did you know that scientists sometimes break these specimens on purpose to better understand them?
As a collections technician in the museum’s Palaeobiology Section, my job often involves removing small pieces of specimens for scientific analyses. Of course, this results in damage to the specimens, but the resulting information from physically and chemically altering the pieces makes it worthwhile.
The national palaeontology collections include an assemblage of Canadian subfossils, organic remains on their way to being mineralized. These subfossils have not become fully encased in rock or had their biological hard parts (bone, tooth, shell, etc.) replaced with a mineral. The greater presence of ancient organic material allows for biochemical sampling, such as radiocarbon dating, stable isotope analysis, and ancient DNA (aDNA, for short) sequencing.
Recently, I sampled walrus (Odobenus rosmarus rosmarus) skeletal elements that were collected from Sable Island in the Maritimes. This group represents a population of walrus that does not exist in the area anymore.
Researchers are currently investigating how large-scale human hunting of walrus populations by whaling crews from the 16th to 19th centuries have affected the species. Stable isotope analyses are underway using museum subfossil samples from the present and earlier. This is being done to better understand the past environment these walruses lived in and how they fit into the food web of their habitat, as recorded by chemical signatures in their bones.
These same researchers also conducted aDNA sequencing to build up the genome of the Sable Island walruses. This will allow them to compare genetic markers in Sable Island walruses to modern walrus populations in both Canadian and European Arctic waters.
The information obtained from these walrus specimens will address multiple questions:
How has the walrus genome changed over time and how much does it differ among populations? Did they live in a different environment or have different feeding behaviours in the past? What impact did humans have on the walrus, both European whalers and Inuit hunters?
These questions can only be more fully explored by conducting destructive biochemical analyses of museum collections. Which is why, after careful consideration, museums will sometimes allow their specimens to be broken!