Final answer:
Primatology research primarily focuses on primate behavior, social systems, cognitive linguistics, evolution, and conservation. Studies on communication in bonobos and the evolution of hominins have been particularly insightful, and conservation research is vital for addressing threats to primates.
Step-by-step explanation:
The principal research interests in primatology cover various aspects, including understanding primate behavior, cognition, evolution, and conservation. By studying nonhuman primates, primatologists and biological anthropologists gain insights into the origins of human intelligence, technology, and culture, while also addressing challenges such as habitat loss and the illegal wildlife trade.
One key area of interest is the investigation of primates' social systems and communication, exemplified by studies on the linguistic abilities of bonobos. Anthropologists like Sue Savage-Rumbaugh have demonstrated that bonobos, with their closely related genetic makeup to humans, can learn to communicate using lexigrams, offering a profound understanding of cognitive linguistics across species. Another major interest lies in the evolution of primates, including the differentiation between Old World and New World monkeys, and the study of hominins, which helps in understanding the trajectory of human evolution.