Monkeys can adapt by changing their diet

Wetlands can be hard places to make a living, and life in fragmented forest amidst wetlands may be even harder. Despite the difficulty, the rare Olalla’s titi monkey (Plecturocebus olallae) has found a way to live in the Llanos de Moxos, the largest wetland in the Amazon Basin. 

New research from the Wildlife Conservation Society (WCS) may explain how the monkeys can survive in the fragmented and damaged forest of the Llanos de Moxos. The scientists observed two groups of Olalla’s titi monkeys for a year. It seems that the key to their survival might be in their ecological flexibility. 

During times of abundance, the monkeys were observed eating fruits and moving around a lot. During the leaner dry season, the monkeys ate less fruit and more leaves, and did not move around as much. They also expanded their diet to include more lichens, seeds and fungi.   

Interestingly, the study shows that monkeys with their ecological flexibility have some ability to tolerate changes in their habitat, such as fragmentation caused by deforestation. 

“The study illustrates the relevance of understanding primate ecological flexibility in response to food reductions to the development of conservation actions, especially in the light of increasing forest degradation and loss in the study region,” said study co-author Rob Wallace, director of WCS’s Greater Madidi-Tambopata Landscape Program.

The scientists believe that these monkeys are still threatened by habitat loss and range limitations. It seems that eventually, even flexible monkeys have a breaking point. The monkeys are already critically endangered and endemic to a small area. 

“The observed shift in diet toward consuming alternative foods during the fruit lean period and reducing movement instead of expanding ranging behavior to look for higher quality foods suggests that P. olallae follows an energy-area minimizing strategy that may enable these primates to inhabit fragmented forests,” wrote the study authors.  

“Nevertheless, deforestation and further fragmentation in the range of these endemic and critically endangered primates must be addressed, as they represent significant threats to the severely range-restricted P. olallae populations.”

The study is published in the International Journal of Primatology.

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By Zach Fitzner, Earth.com Staff Writer