Monkey see, monkey go: How climate change, deforestation are putting some primates in a bind

• Primates already face “unprecedented challenges,” researchers said, and climate change is likely to bring additional burdens, according to the study.
• The study by a group of more than 100 researchers found species in large social groups or in hotter places with less canopy cover might be pre-wired to adapt to change.

Some species of monkeys, lemurs and other primates may be leaving their leafy homes more often as the warming climate affects tree canopies in their forests, according to a new study by a group of more than 100 researchers.

Human activities that bring hotter temperatures and deforestation send arboreal primates to the ground more often in Central and South America and Madagascar, increasing their risk of interaction with people and predators, the study reported.

That could ultimately, however, give them an edge over primates that can’t adapt as easily. 

Primates already face “unprecedented challenges,” researchers said, but the paper published Monday in the Proceedings of the National Academy of Sciences suggests they’ll encounter additional burdens from climate change. It examines which traits help primates adapt to change.

A multi-faceted diet and living in larger groups appear to give some species an advantage, said the study’s lead author, Timothy Eppley, a postdoctoral associate at the San Diego Zoo Wildlife Alliance. While they adapt by dropping to the ground more often, other species do not and may need higher priority conservation efforts, Eppley said.  

During 150,000 hours of observation, they studied 15 lemur species, and 32 species from four families that include howler monkeys, tamarins, capuchins and squirrel monkeys. 

Putting together such a massive amount of information was “a huge job” by Eppley, said co-author Karen Strier, a professor in the University of Wisconsin-Madison’s anthropology department. Strier has studied the northern muriqui, a primate species in Brazil since 1982. 

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Eppley started the project after noticing some species of bamboo lemurs in Madagascar spent more time on the ground, while the same animals in less-disturbed locations never descended.

Researchers found species in large social groups or in hotter places with less canopy cover might be pre-wired to adapt to change, Eppley said. 

Primates that live farther away from roads and people spend more time on the ground than those living closer to people, which may suggest humans interfere with their natural adaptability, stated Luca Santini from Sapienza University of Rome, a senior scientist who collaborated on the study. 

Many species are already burdened with living in fragmented and heavily disturbed environments with fewer food sources. The authors concluded an ability to eat other kinds of plants and not just fruit, and to spend time on the ground in areas where tree cover is sparse and temperatures are warmer may help buffer species against extinction. 

Other species, such as some of the lemurs in Madagascar, eat only fruit and need forest habitat, which is rapidly declining, Eppley said. 

The world’s fourth largest island, Madagascar has a population of nearly 28 million people. Forests and lands are being cleared for agriculture and also are battered by tropical cyclones, increasingly fueled by warmer sea surface temperatures. 

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However, primates who leave the canopy face new predators on the ground, particularly feral dogs and cats. In Madagascar, he said, feral dogs and cats outcompete the island’s natural predators.