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Daily Defecation Outputs of Mountain Gorillas

Output takes center stage in this new study of what some gorillas left behind:

Daily Defecation Outputs of Mountain Gorillas (Gorilla beringei beringei) in the Volcanoes National Park, Rwanda,” Elie Sinayitutse, David Modry, Jan Slapeta, Aisha Nyiramana, Antoine Mudakikwa, Richard Muvunyi, and Winnie Eckardt, Primates, epub 2020. (Thanks to Damien Caillaud for bringing this to our attention.)

The authors, at the Dian Fossey Gorilla Fund International; the University of Rwanda, Butare; the University of Veterinary and Pharmaceutical Sciences, Czech Republic; the Czech Academy of Sciences; the University of Sydney, Australia; the University of Rwanda; and the Rwanda Development Board, report:.

“We weighed 399 wet fecal samples deposited at nest sites and on trails between nest sites by gorillas of varying age and sex, determined by lobe diameter, from five social groups (n = 58 gorillas) that range in the Volcanoes National Park, Rwanda. We found increasing daily average defecation outputs with increasing age-sex class (infants, 435 g; juveniles, 1346 g; medium-sized gorillas, 2446 g; silverbacks, 3609 g). Gorillas deposited two– to threefold the amount of feces at nest sites compared to on trails, suggesting that nest sites may function as hotspots for enteric pathogen infections through direct contact or when gorillas ingest foods contaminated with infectious larvae during site revisits in intervals matching the maturation period of environmentally transmitted gastrointestinal parasites.”

PERSONAL (by Marc) NOTE: In my 9th grade biology class the teacher gave me an F on a book report, because she insisted I was concocting the details. The details were about observing gorilla droppings. The book, I’m pretty sure, was either by or about Dian Fossey. The teacher was so angry at me that, even after I retrieved the book from the library and showed her the things I had described she still insisted on giving me an F for that report. It’s the only F I ever got, and I am still proud of it.

Improbable Research