The pattern and drivers of taxonomic bias in global primate research

Given that 64% of nonhuman primate species are threatened with extinction, science-based conservation action is urgently needed to protect their imperiled populations. However, lack of key information on species due to a research bias can hinder effective conservation actions. We examined taxonomic bias in global primate research and employed phylogenetic mixed models to assess potential factors that have shaped this bias. Using the Scopus database, we analyzed 90,568 articles on primates published from 1950 to 2021 in 33 languages. We found that annual publications on primates increased over time, but conservation-focused publications accounted for only 4.3% of those we analyzed. We identified a strong taxonomic bias in primate publications, with a small set of species being predominant. In all, 43.0% of all primate species (224/522) had < 10 publications. Phylogenetic comparative analyses showed that species which are small, arboreal, ranged into fewer countries, and inhabited field sites with limited accessibility were the least studied. Although 67.7% of 5863 conservation publications focused on threatened species, 46.8% of threatened species (163/348) had only 0-3 conservation publications, suggesting crucial knowledge gap still existed. This lack of knowledge limits our ability to develop effective conservation solutions. We suggest that granting agencies, governments, scientists, and the academic community prioritize funding and research of overlooked threatened primate species to avoid an emerging extinction crisis.