Effect of climatic seasonality and food availability on the activity budget and the diet of black and gold howler monkeys (Alouatta caraya)

ZUNINO, GABRIEL E; PAVE, ROMINA E; BRIVIDORO, MELINA; KOWALEWSKI, MARTIN

Primatology in Argentina

Sociedad Argentina para Estudio de los Mamíferos SAREM

Lugar: Mendoza; Año: 2017; p. 106 - 125

The activity budgets and diets of primates are influenced by climatic seasonality and day length. Here, we examined the effect of seasonality and food availability on the activity budget and diet of black and gold howler monkeys (Alouatta caraya). These monkeys are living near the southern limit of their geographic distribution in a subtropical environment, near a transitional limit to being a warm and temperate climate. Their habitat is characterized by seasonal fluctuations in temperature and day length. In the winter months, days are colder and about three hours shorter than in the summer. Fall and spring are intermediate in terms of temperatures and day length. There was a marked seasonality in resource availability, mainly in seasonal foods: new leaves, flowers, and fruits. Non-seasonal foods, mostly mature leaves, were less variable and more abundant throughout the year. The monkeys? activity budget and diet composition differed between seasons. Their time spent resting was highest in the summer and lowest in the spring. Their time spent moving and engaging in social activities was highest in the spring, the season with the greatest availability of seasonal foods. Temperature had no influence on their activity budget. There was a negative relationship between the abundance of non-seasonal foods and time spent feeding, and also between the abundance of seasonal foods and time spent resting. The abundance of seasonal foods positively correlated with time spent moving and engaging in social activities. During the spring, their diet was dominated by new leaves. In the summer and early fall, their diet consisted mainly of mature leaves and fruits. Our results indicate that seasonality influences both the activity budget and diet of Alouatta caraya living near the southern limit of their distribution. The periods of time with low availability or absence of seasonal foods may be the key variable in determining the limits for primate geographic distribution towards the southern latitudes.