Legendary primatologist Dian Fossey spent decades documenting the lives of the mountain gorillas of Rwanda. Now, scientists are exhuming the bodies of those gorillas to learn about evolution. Researcher Erin Marie Williams is part of that team and sent this third dispatch from the field.
There are seven cervical, 13 thoracic and three lumbar vertebrae in each mountain gorilla (unless there aren't, which is rather common), making a grand total of 23 (more or less). Hands and feet have 19 bones, 27 if you count the wrist and ankle bones. There are also 26 ribs, six leg bones and six arm bones (we're at 169 bones, if you're keeping count). Throw in two clavicles, two scapulae, two patellas, and some skull bones, and you've got well over 200 bones in one mountain gorilla.
Last year, before we arrived, the crew here recovered, cleaned, photographed and cataloged over 70 mountain gorillas. If you do the math, this means that they sorted through hundreds of mountain gorilla bones in just six weeks.
Picking Up The Pieces
Today, at the Karisoke Research Center's garage, it took me all morning to sort out the hands and feet of a single male gorilla. Or maybe it was just one hand and one foot. However, Rome was not built in a day.
Fortunately my colleagues are far more proficient than I am. While I labored over my one hand and one foot, Amandine Eriksen, one of the two forensic anthropologists on the crew, laid out the rest of the skeleton of a female adult gorilla for photographing and cataloging.
Amandine is from the University of Indianapolis and is here along with her graduate adviser, anthropologist Stephen Nawrocki. Together they can catalog basically every bump and bruise each gorilla experienced in life. The number of everyday incidents that leave long-term marks on bone is astounding. Drop something on your pinkie toe, and two of your toe bones may grow together. Bump your leg hard enough and it can cause new bone to grow on your shin.
Examining The Bones
Where I see a lump on a bone, they see a broken wrist that healed with time, but not quite in the correct orientation. They know it would have caused the gorilla to walk with a slight limp on the right side and to put most of its weight on the other arm, which, by the way, explains why that other arm is so much larger. Once they really get going on a skeleton, they reach a sort of rhythmic cadence. Terms like "osteochondritis dissecans," "diffuse idiopathic skeletal hyperostosis" and (my favorite) "ankylosing spondylitis" may have no meaning to me, but the terms make a sort of poetry of pathology.
The idea here is to compare these marks on the bone with what Rwandans and others who've chronicled the lives of these gorillas have recorded. That way we can understand how life leaves a history in the bones, not just for gorillas but for all primates, including humans.
Today, Amandine documented one very poorly preserved female gorilla skeleton. By the time she finished she had determined that this gorilla had possibly broken one wrist, lived with osteoarthritis in her left foot and probably throughout her body, had one leg bone that was shorter than the other, extra bone growth on another leg bone, and had worn her teeth nearly to the point of uselessness. The records kept by the vets and trackers here in Rwanda will help confirm or refute what Amandine sees in the bones.
All of the Rwandan gorillas have health care provided by the Mountain Gorilla Veterinary Project and the national parks authorities, so their conditions are frequently monitored. In fact, all Rwandans have state-provided health care, too. Perhaps we should send someone over here from the U.S. to study Rwanda's health care system.
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