Rhesus macaques became more social after Hurricane Maria

  • Monday, April 19, 2021

New research has demonstrated that macaques in Cayo Santiago, Puerto Rico became more social after the devastating Hurricane Maria hit the Caribbean in 2017. The research, led by the University of Pennsylvania, was contributed to by a master’s project conducted by our former MRes Primate Biology, Behaviour and Conservation student Cassandre Kaplinsky. She and her project supervisors, Dr Harry Marshall and Dr Julia Lehmann of our Department of Life Sciences, are co-authors on the paper.

Image - Rhesus macaques became more social after Hurricane Maria

In 2017, Hurricane Maria devastated parts of the Caribbean, leaving over 3,000 people dead and causing wide-spread damage and destruction. Cayo Santiago island in Puerto Rico, home to a population of rhesus macaques, was devastated by the same storm.

The research team compared the social networks of two groups of macaques before and after the hurricane and found an increase in friendly social connections. The team also found that macaques who were socially isolated before the storm increased social connections the most after it.

To broaden their social networks, the macaques built new relationships rather than strengthening existing ones. To do this they adopted a “path of least resistance” approach by reciprocating grooming interactions and closing triads - that is becoming friends with the friends of your friends - a frequent mechanism for bond formation across the animal kingdom, including in humans.

After the hurricane, green vegetation in Cayo Santiago declined by 63%. The island was almost completely deforested, making shade from the sun a scarce resource. When trying to access a scarce resource like shade, having stronger bonds isn’t necessarily useful. Instead, it seems the macaques turned to a higher number of non-kin after the hurricane, giving them access to more areas of shade.    

The results found by the research team are consistent with a group-level response to an extreme life event of Hurricane Maria’s magnitude, in which individuals become more tolerant of one another and seek contact with unfamiliar partners.

With the intensifying climate crisis, devastating storms are expected to become less predictable, and increase in both frequency and force. Understanding how individuals adjust and survive in severely transformed landscapes could inform species conservation and human adaptation to increasingly unstable environments by providing evidence regarding which factors promote resilience and survival.

Our Department of Life Sciences offers outstanding undergraduate and postgraduate degrees including our MRes Primate Biology, Behaviour and Conservation, and our MbyRes Ecology, Evolution and Behaviour.