RESUMO
In May and June 2024, a die-off of Mexican mantled howler monkeys (Alouatta palliata mexicana) occurred in southern Mexico. This commentary documents the event, attributing it to extreme heatwaves, drought, wildfires, and habitat impoverishment. Despite their reported resilience to habitat disturbances, mantled howler monkey mortality rate in some areas reached 31%. Key evidence points to heatstroke as the primary cause of death, exacerbated by limited hydration and reduced dietary diversity in disturbed habitats. Immediate responses included community-led rescues (e.g., hydrating the monkeys), coordination of rescue activities by nongovernmental organizations (NGOs) (e.g., managing donations), involvement of scientists (e.g., monitoring of primate populations), and assistance from government officials (e.g., providing legal support for animal management). This event underscores the urgency of developing action plans to prevent and attend future crises. Among other actions, we highlight (i) establishing primate care infrastructure with medical and rehabilitation centers; (ii) developing protocols and training programs to ensure rapid crisis response; (iii) fostering collaboration among government, NGOs, and academic institutions for effective crisis management; and (iv) developing targeted research on climate change impacts, predictive models, and long-term health monitoring. We emphasize the critical need for coordinated conservation efforts to protect wild primates and maintain natural ecosystem resilience in the face of escalating climate challenges.
RESUMO
Deforestation is widely recognised as an agent of human disturbance that causes widespread destruction of species habitats and can result in animals occupying forest patches with limited food resources. When animals are forced to change habitats, they must also adjust their diet, activity budgets and social behaviour in response to facing new ecological and environmental conditions. Only a few studies have analysed the influence of habitat conditions on social interactions of immature howler monkeys. In this study, we examined the effects of variation in food availability on social interactions of young howler monkeys (Alouatta palliata mexicana). This was accomplished by observing infant and juvenile members of two groups inhabiting a continuous forest habitat (640 ha) and three groups living in different-sized forest fragments (4, 42 and 93 ha) for a 15-month non-consecutive period. We quantified the Potential Food Availability Index (PFAI) for each habitat type based on the basal area, the Shannon-Wiener diversity index and abundance of food tree species. We used 15-min focal animal sampling to record the occurrence and/or duration of affiliative and agonistic behaviours. In habitats with higher PFAI, we observed more social play and proximity in infants aged 4-7 months, grooming in infants aged 8-14 months and social play in juveniles. Conversely, juveniles' grooming rates and 0- to 3-month-old infants' proximity rates decreased as PFAI increased. Our results suggest that food resource variation influences young howler monkeys' social interactions. The reduction in social interactions due to low food availability may represent an energy-saving strategy to cope with limited resources in habitats disturbed by anthropogenic activities.