How orca bones were cleaned and prepared for articulation

So many bones to clean!

In March 2009, PTMSC received the bones from NOAA and started the final phase of bone cleaning and whitening. Most of the bones only required a three-day soak in hydrogen peroxide, followed by a sunny, slow dry in a warm greenhouse. Other bones needed extra attention to remove the last bits of cartilage or wood chips left over from the manure pile. A few bones needed yet another round of treatment to remove the persistant, strong-smelling oil. Cleaning the bones has been one continuous experiment. We learned that a number of different methods are used by the experts, but each skeleton and even each bone may require its own unique treatment.

And what about the skull?

During the necropsy on the beach, the head had been removed, frozen, and sent to California to be scanned (MRI) to learn if the orca had suffered damage from sonar or some other cause. The scan revealed a largeabscess at the base of her skull. This was probably from a brucellosis infection, since a tissue culture taken of the carcass had shown signs of the bacteria causing that disease. This infection, combined with an immune system compromised by a heavy dose of toxins, was probably a significant factor in her death – although likely not the main cause.

After soaking in the NOAA lab for much of the winter, the skull was transferred to PTMSC in the fall of 2009. Staff and volunteers soaked and scraped it, removing the last bits of tissue and cartilage. They soaked it again, then put it in a sunny, warm environment for final drying and whitening during the summer of 2010.

The "missing" flipper

When we excavated the skeleton back in 2008, we found only one of the flippers. The scientists who had buried it six years earlier scratched their heads, trying to think where it might be. A few minutes later, Brad Hanson (NOAA) recalled that he had removed it from the carass when it was buried and put it in the NOAA freezer.

He had done this knowing that the skeleton might some day be articulated, and realizing that if the flipper were preserved, an x-ray or CAT scan could be taken that would make it much easier to reassemble the small bones accurately.

We retreived the flipper and were able to have it scanned.

To get the bones out of the flipper we had to cook it. But first we wanted to make sure we recorded its exact size and shape. Our AmeriCorps members measured its dimensions and printed it onto fabric so we would have an exact record for later.

The number of bones and their position in the flipper varies from whale to whale, but the CAT scan and the flipper print will serve as a useful blueprint for when we put the bones back together for the final exhibit.

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