What 2 species of nonhuman primates are most used?

• A. Marmoset and Squirrel monkey
• B. Rhesus and Cynomolgus
• C. Baboon and Gibbon
• D. Chimpanzee and Gorilla

Answer: (B)

Rhesus and cynomolgus macaques are the most used nonhuman primates in research because they offer a strong balance between relevance to human biology and practical usefulness in the lab. Their physiology, immune system, and organ function are very similar to humans, which makes data from these species more predictive for human responses. They are of a workable size and temperament for routine procedures, and there is a long, well-established infrastructure around their care, breeding, and experimental use. This includes extensive historical data, validated assays, and readily available reagents, which accelerates study planning and interpretation. Because of these factors, they are widely employed across a broad range of fields, from infectious disease and vaccine research to toxicology and neuroscience.

Other primates, like smaller New World species, are used in certain contexts but don’t match the breadth of translational applicability and the level of established resources that these macaques provide. Chimpanzees and gorillas face stringent ethical and legal restrictions; baboons and gibbons are used in some niches but are less common overall.