• Energy Research

As the effects of global climate change become more apparent, animal species will become increasingly affected by extreme climate and its effect on the environment. There is a pressing need to understand animal physiological and behavioural responses to climatic stressors. We used the reactive scope model as a framework to investigate the influence of drought conditions on vervet monkey ( Chlorocebus pygerythrus ) behaviour, physiological stress and survival across 2.5 years in South Africa. Data were collected on climatic, environmental and behavioural variables and physiological stress via faecal glucocorticoid metabolites (fGCMs). There was a meaningful interaction between water availability and resource abundance: when food availability was high but standing water was unavailable, fGCM concentrations were higher compared to when food was abundant and water was available. Vervet monkeys adapted their behaviour during a drought period by spending a greater proportion of time resting at the expense of feeding, moving and social behaviour. As food availability decreased, vervet mortality increased. Peak mortality occurred when food availability was at its lowest and there was no standing water. A survival analysis revealed that higher fGCM concentrations were associated with an increased probability of mortality. Our results suggest that with continued climate change, the increasing prevalence of drought will negatively affect vervet abundance and distribution in our population. Our study contributes to knowledge of the limits and scope of behavioural and physiological plasticity among vervet monkeys in the face of rapid environmental change.

As the effects of global climate change become more apparent, animal species will become increasingly affected by extreme climate and its effect on the environment. There is a pressing need to understand animal physiological and behavioural responses to climatic stressors. We used the reactive scope model as a framework to investigate the influence of drought conditions on vervet monkey ( Chlorocebus pygerythrus ) behaviour, physiological stress and survival across 2.5 years in South Africa. Data were collected on climatic, environmental and behavioural variables and physiological stress via faecal glucocorticoid metabolites (fGCMs). There was a meaningful interaction between water availability and resource abundance: when food availability was high but standing water was unavailable, fGCM concentrations were higher compared to when food was abundant and water was available. Vervet monkeys adapted their behaviour during a drought period by spending a greater proportion of time resting at the expense of feeding, moving and social behaviour. As food availability decreased, vervet mortality increased. Peak mortality occurred when food availability was at its lowest and there was no standing water. A survival analysis revealed that higher fGCM concentrations were associated with an increased probability of mortality. Our results suggest that with continued climate change, the increasing prevalence of drought will negatively affect vervet abundance and distribution in our population. Our study contributes to knowledge of the limits and scope of behavioural and physiological plasticity among vervet monkeys in the face of rapid environmental change.

We report the death of 30 wild Barbary macaques, living in two groups, during an exceptionally cold and snowy winter in the Middle Atlas Mountains, Morocco. We examined whether an individual's time spent feeding, the quality and number of its social relationships, sex and rank predicted whether it survived the winter or not. The time an individual spent feeding and the number of social relationships that an individual had in the group were positive and significant predictors of survival. This is the first study to show that the degree of sociality affects an individual's chance of survival following extreme environmental conditions. Our findings support the view that sociality is directly related to an individual's fitness, and that factors promoting the establishment and maintenance of social relationships are favoured by natural selection.

We report the death of 30 wild Barbary macaques, living in two groups, during an exceptionally cold and snowy winter in the Middle Atlas Mountains, Morocco. We examined whether an individual's time spent feeding, the quality and number of its social relationships, sex and rank predicted whether it survived the winter or not. The time an individual spent feeding and the number of social relationships that an individual had in the group were positive and significant predictors of survival. This is the first study to show that the degree of sociality affects an individual's chance of survival following extreme environmental conditions. Our findings support the view that sociality is directly related to an individual's fitness, and that factors promoting the establishment and maintenance of social relationships are favoured by natural selection.