Investigating factors of metabolic bone disease in baboons (Papio spp.) using museum collections

Objectives To assess manifestations of metabolic bone disease (MBD) and their potential environmental and phenotypic factors in captive and non‐captive baboon (Papio spp.) specimens. Materials and methods Our sample consisted of 160 baboon specimens at the Smithsonian's National Museum of Natural History accessioned from 1890 to 1971. Combining cranial indicators of MBD and the museum's historical data, we examined factors contributing to likely instances of MBD. We used binomial‐family generalized linear models to assess differences in MBD frequency by environment (captive, non‐captive), specimen accession year, and skin color (light, medium, dark). Results Indicators of MBD were most frequently observed in captive baboons, with a decrease in MBD frequency over time. Fifteen non‐captive individuals showed indicators of MBD, which are the first published cases of MBD in non‐captive nonhuman primates (NHPs) to our knowledge. The most common MBD indicators were bone porosity (n = 35) and bone thickening/enlargement (n = 35). Fibrous osteodystrophy was observed frequently in our sample, likely relating to nutritional deficiencies. We found no association between exposed facial skin color variation and MBD. Conclusions Our findings are consistent with historical accounts of MBD prevalence in captive facilities, especially earlier in the 20th century. A decrease in MBD prevalence later in the 20th century likely reflects improvements in housing, diet, and veterinary care in captive settings. Causes of MBD development in non‐captive baboons should be further explored, as understanding the potential health impacts that anthropogenic environments impose on NHPs is imperative as humans increasingly alter the natural world in the 21st century. Baboon crania that exhibit variation in metabolic bone disease presentation (b, c), compared to a cranium without disease (a).