2023 was a banner year for the National Museum of Natural History marked by the arrival of significant specimens, the unveiling of multiple exhibitions and hundreds of scientific publications. Join us for the “NMNH in Review” series over the next month to learn about a new orca specimen, historic asteroid samples and other exciting discoveries made by museum scientists this year. Read previous installments here.
Scientists wearing brightly colored gloves pulled vertebrae after vertebrae from bulging black trash bags in a Smithsonian lab as jets of water removed chunks of flesh from a colossal skull. Nearby, ribs were stacked like bundles of firewood on a sterile metal examination table. Suddenly, the amalgamation of scattered bones began to fit together like the pieces of a biological puzzle as a majestic marine mammal took shape.
The 21-foot skeleton belongs to Orcinus orca, the largest member of the dolphin family. Although the striking sight (and smell) of such a skeleton may make many people squeamish, the National Museum of Natural History’s marine mammal specialist, John Ososky, had been waiting months to get his hands on the oversized specimen. The excitement was palpable as Ososky and a team of collections specialists rushed around the Osteo Prep Lab at the Smithsonian’s Museum Support Center noting every nick, scratch and crack on the dirt-encrusted bones.
In early January 2023, a female orca was found stranded near Palm Coast, Florida, immediately sparking the interest of marine mammal researchers all along the Eastern Seaboard. In a collaborative effort, scientists from the National Oceanic and Atmospheric Administration (NOAA) and the Florida Fish and Wildlife Conservation Commission performed a post-death examination of the specimen, collecting tissue and DNA samples that will be used to analyze the orca’s life and potentially explain her death.
When Ososky heard about the orca, he immediately knew that he wanted it for the Smithsonian’s collections. In North America’s crowded coastal waters, human activity has depleted marine food resources and created a host of environmental hazards. As a result, orca populations have dwindled over the years, making these strandings increasingly rare.
Although Ososky has processed close to 1,500 specimens during his 25 years at the museum, this was the first orca stranding he had ever responded to. “This is a very rare animal, so every bit of data we get is precious,” Ososky said. “Each specimen can help us understand how the species is changing through time, which has become harder and harder to assess.”
After the orca was taken to the University of Florida in Gainesville for a forensic study, Ososky requested that the specimen be covered in hay and compost material for 5 months to allow the remains to skeletonize. When Ososky and NMNH vertebrate zoology museum technician Teresa Hsu arrived to collect the specimen, the compost pile was hot to the touch. The heat was a strong indicator that the decomposition process was nearly complete, and the microbes in the compost material had broken down the whale’s organic matter.
An unusual August road trip brought the orca to the Smithsonian. Despite the nose-wrinkling smell, other drivers on the road may never have guessed what was inside of the mountain of bags piled in the back of a pickup truck. At the Osteo Prep Lab, the skeleton was carefully laid out on the floor as Ososky and Hsu took their first thorough look at the museum’s newest marine mammal specimen.
Almost instantly, Ososky and Hsu noticed that this skeleton looked different than anything they had ever seen before. Unlike many of the orca specimens in the Smithsonian’s collection, these bones were covered with imperfections that had accumulated over time.
“This skeleton has a lot of character to it for the same reason I have a lot of character to me: it’s old,” Ososky said with a laugh. “You can see her life history written in the holes and cracks in her bones, and it’s one of the things that makes this specimen very unique.”
This represents the first complete skeleton of a mature orca in the Smithsonian’s marine mammal collection, offering valuable research insights not seen in juvenile specimens.
To determine the exact age of the orca, scientists from the Florida Fish and Wildlife Conservation Commission are planning to cut into the specimen’s teeth to count the growth rings that accumulated over the animal’s lifetime. But according to Hsu, the plates at the ends of the whale’s vertebrae were completely fused, a characteristic that occurs only when a mammal reaches maturity.
The researchers pinpointed a large hole in one of the vertebrae and signs of old age on the whale’s scapula. “The vertebra should be solid, but this one is hollowed out like a bowl due to a long-standing infection,” Hsu said. “This would have been painful for the animal and restricted movement, and it’s clear that orca’s body was trying to react to it.”
This infection and bone degradation could have been caused by disease, arthritis or even a ship strike. According to Ososky, human interaction damage is commonly found on whale, dolphin and other marine mammal specimens. Although researchers may never be able to determine this orca’s cause of death, a closer analysis of the bones using CT and laser scanning will help give context to the various injuries on its skeleton.
Once the initial analysis of the skeleton had been completed, the specimen underwent months of thorough cleaning. While the Osteo Prep Lab has an abundance of skeletal preparation methods at its fingertips, Ososky was confident that macerating, or soaking, the specimen would be the least harmful and most effective plan. Submerging the bones in water allowed natural microbial action to break down any remaining bits of grease and organic material. A quick bath in ammonia got rid of the fishy odor that stuck to the bones.
The skeleton is now through 90% of the cleaning process, and Ososky has begun numbering the bones to prepare them for installation in the Smithsonian’s marine mammal repository. The bones will be available to researchers from around the world and could help answer some big questions in marine mammal science.
Although there are over 10 different varieties of orca, each with their own distinct size and characteristics, there is only one option when classifying this specimen. “It has to be Orcinus orca,” Ososky says. “That's the only recognized species of orca at the moment.”
Many researchers believe that all orca varieties should be separated into distinct species. The technological tools needed to make these genetic and physical distinctions are becoming increasingly advanced. However, in order to compare orca varieties, scientists need to examine mature specimens that are fully developed.
In a marine ecosystem that is facing the effects of human interactions, it is rare for orcas to survive to advanced ages. Every specimen that has lived past the juvenile stage offers new opportunities for research into the complexities and differences between orca varieties and populations. “We want to compare apples to apples, not apples to oranges,” Ososky said. “It’s another reason why this complete, mature specimen is scientifically valuable and such a necessary addition to this collection.”
A specimen like this will also attract the interest of scientists from around the globe, helping them to investigate questions specific to their own research. According to NMNH’s curator of marine mammals, Michael McGowen, “my postdoc Ellen Coombs and I will be scanning the jaws as part of a study on jaw morphology and ecology in killer whale groups called ‘ecotypes’ that feed on different things.”
Researchers from NOAA and the Florida Fish and Wildlife Conservation Commission have taken genetic samples that could be used to link the whale with other populations. This research should be able to explain where this orca originated, and why it was down near the Gulf of Mexico when it died.
As the first and only mature orca skeleton in the collection, this specimen will be a crucial addition to the Smithsonian’s global repository, the largest and most diverse marine mammal collections in the world at 18,000 species strong. This unique data point will allow generations of future researchers to study and further understand this species.
“If I were to sum up natural history science in one phrase, it would be ‘change over time,’” Ososky said. “Orcas are just endlessly fascinating creatures and studying how they are changing in today’s world has become more important than ever.”
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