Monkeys are among the most diverse and charismatic animals in the world, but they are also facing a serious threat from big cats, especially in tropical forests that have been damaged by human activities.
A new study by a researcher from the University of Oxford has revealed how big cats, such as jaguars, leopards, and pumas, prey more on monkeys in degraded forests than in intact ones, and how this could have negative consequences for the survival of primates populations and the carbon storage of the forests.
Big cats prefer monkeys in degraded forests
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The study, published in the journal Biological Conservation, used camera traps to monitor the hunting behavior of big cats and the abundance of monkeys in 16 sites across four countries: Brazil, Peru, Colombia, and Indonesia.
The sites ranged from pristine forests to those that had been logged, burned, or converted to agriculture.
The researcher found that big cats hunted monkeys more frequently in degraded forests than in intact ones, and that this was not explained by the availability of other prey, such as rodents or deer.
The researcher suggested that this could be because monkeys are easier to catch in degraded forests, where the canopy is more open and the vegetation is less dense.
Monkeys also tend to congregate in larger groups in degraded forests, possibly to avoid predation by raptors, which makes them more visible and attractive to big cats.
The researcher also found that the hunting pressure of big cats varied depending on the species of monkey and the type of forest.
For example, jaguars hunted more spider monkeys and howler monkeys in logged forests, while leopards hunted more macaques and langurs in burned forests.
Moreover, pumas hunted more capuchins and tamarins in agricultural areas, where they also faced competition from domestic dogs.
Monkeys are important for forest health and carbon storage
The increased predation of monkeys by big cats in degraded forests could have serious implications for the health and resilience of the forests, as well as their ability to store carbon and mitigate climate change.
This is because monkeys play a vital role in dispersing the seeds of many hardwood tree species, which are often large, heavy, and encased in hard shells.
Monkeys can swallow these seeds whole and pass them through their digestive system, or spit them out after eating the fruit pulp.
Either way, they help to disperse the seeds far and wide, and increase their chances of germination and survival.
Hardwood trees are important for the structure and diversity of tropical forests, as they provide habitat and food for many other animals and plants.
They are also important for carbon storage, as they can grow to great heights and live for hundreds of years, accumulating large amounts of carbon in their biomass.
However, hardwood trees are also the most vulnerable to logging, fire, and climate change, as they are slow-growing and have low regeneration rates.
The loss of monkeys due to big cat predation could reduce the seed dispersal and regeneration of hardwood trees, and thus affect the carbon storage capacity of the forests.
A previous study estimated that the loss of primates could result in a 2.5% reduction in carbon storage across the tropics, equivalent to 12 years of global fossil fuel emissions.
This could exacerbate the feedback loop between deforestation and climate change, and undermine the efforts to conserve and restore tropical forests.
