Johnson is a Research Associate in the Departments of Experimental Psychology and Psychiatry at the University of Oxford. The researchers focused on one social group of macaques (22 males and 16 females aged twenty-six years) on the island of Cayo Santiago, off the east coast of Puerto Rico. Macaques were only once found in North Africa and Asia. However, in 1938, 409 rhesus macaques were transferred from India to Cayo Santiago. On the 15.2-hectare island today, more than 1,000 macaques are divided into several social groups. They are free to roam and forage, although their diet supplement the monkeys’ food daily. Every year, researchers conduct behavioral studies on monkeys.
“Macaques are very social animals, and grooming is their main way of forming and maintaining relationships, so grooming provides a good indicator of social interactions,” said co-author Dr. Carly Watson of the University of Colorado Boulder’s Institute of Cognitive Sciences.
“Participation in social interactions was positively correlated with the abundance of certain gut microbes with beneficial immune functions, and negatively correlated with the abundance of potentially pathogenic organelles,” said co-author Dr Philip Burnett, a professor from the University of Oxford. Department of Psychiatry.
Phykalibacterium and Prevotella, for example, were more abundant in more social monkeys. Streptococcus, which can cause diseases such as strep throat and pneumonia in humans, is found in abundance in less socialized monkeys.
