Typically, the term “primates” evokes images of macaques, a species that is often seen in zoos or on television. These animals are known for their meticulous grooming habits and their complex social structures that include alliances, coalitions, and hierarchies. However, another species of primate that deserves attention is the mantled howler monkey or Alouatta palliata. This is a species that is currently endangered and has not been studied extensively. The intricacies of their social interactions remain largely unknown.
At the Institute of Neuroethology of the Universidad Veracruzana, a team of researchers has dedicated their efforts to study this species. The institute has a history of working with primates for over three decades. The mantled howler monkeys they study are found primarily in the Mexican southeast, specifically in the Los Tuxtlas Biosphere Reserve.
The research team is led by Pedro Dias and Ariadna Rangel-Negrín and consists of several researchers from the Universidad Veracruzana and other educational institutions. It also includes undergraduate and graduate students. The team size varies depending on the research projects being undertaken on these primates.
In an interview with The Day, Dias expressed that his initial interest in primates arose from a desire to understand human evolution and behavior. However, as his research progressed, he began to recognize the crucial role these animals play in preserving tropical forests. He has documented numerous ecological interactions in which they play a part.
Dias emphasized that while macaques are known for their vibrant social activity, the social dynamics of howler monkeys are more subtle and less understood. Despite this, they exhibit social behavior, live in cohesive groups, rear their young, and form long-term relationships. The mantled howler monkeys are, without a doubt, sociable creatures.
Despite being an endangered species, the mantled howler monkey has not been studied extensively. Dias noted that most research on this species is outdated or conducted in different geographic regions. The institute aims to contribute to the understanding of these animals by conducting thorough research. To do this, they use two approaches: studying the behavior of these animals in their natural habitats and examining the impact of human disturbance on their ecosystems.
In line with these two perspectives, the team has conducted research on mother-infant relationships in howler monkeys. They aim to understand if there are distinct styles of maternal care among these animals. They also investigate how these animals react to the sounds of predators that are no longer present in their environment to determine if they can still recognize these threats.
This involves simulating the sounds of natural predators in areas where these predators still exist. Then they repeat the process in areas where these predators are extinct to see if there’s a difference in the monkeys’ ability to recognize these threats.
Dias stressed the importance of this research. If predators such as the harpy eagle were reintroduced into the howler monkeys’ habitat, the monkeys could be in danger if they fail to recognize them as threats.
The research team also studies the interactions between the howler monkeys and the screw fly, known as moyocuil. This fly is of interest because it appears to regulate howler monkey populations. While an infestation of screw flies doesn’t typically kill a howler monkey, if the monkey is already compromised due to infection or lack of food, the additional burden of parasites can increase the likelihood of death. Given that the mantled howler monkey is an endangered species, understanding the impact of parasitism is crucial.
Dias concluded by stating that the team’s work is focused on basic research. They aim to answer questions that are currently unknown. This pursuit of knowledge is driven by their innate curiosity.
