Sleeping Site Selection by Agile Gibbons: The Influence of Tree Stability, Fruit Availability and Predation Risk

Primates spend a significant proportion of their lives at sleeping sites: the selection of a secure and stable sleeping tree can be crucial for individual survival and fitness. We measured key characteristics of all tree species in which agile gibbons slept, including exposure of the tree crown, root system, height, species and presence of food. Gibbons most frequently slept in Dipterocarpaceae and Fabaceae trees and preferentially chose trees taller than average, slept above the mean canopy height and showed a preference for liana-free trees. These choices could reflect avoidance of competition with other frugivores, but we argue these choices reflect gibbons prioritizing avoidance of predation. The results highlight that gibbons are actively selecting and rejecting sleeping trees based on several characteristics. The importance of the presence of large trees for food is noted and provides insight into gibbon antipredatory behaviour

Hybridization in howler monkeys: current understanding and future directions

Hybridization, or the process by which individuals from genetically distinct populations (e.g., species, subspecies) mate and produce at least some offspring, is of great relevance to understanding the basis of reproductive isolation and, in some cases, the origins of biodiversity. Natural hybridization among primates has been well known for a few taxa, but just recently the genetic confirmation of hybridization on a number of taxa has produced new awareness of the prevalence of this phenomenon in primates and its importance in primate evolution. The study of hybridization of Alouatta pigra and A. palliata in Mexico was among the first to genetically confirm the current occurrence of hybridization in primates. Following this study, other reports of hybridization across primate taxa have shown that this phenomenon is more widespread in the Primate order than was initially expected. Within the genus Alouatta, there have been reports on the presence of hybridization between A. caraya and A. guariba in a number of contact zones in Brazil and Argentina, and various studies are currently ongoing in some of these sites to understand the extent and patterns of hybridization between these species. In this chapter, we evaluate the extent of hybridization in the genus Alouatta, revise the current knowledge of the genetic and morphological aspects of these hybrid systems, and identify future directions in the study of hybridization within this genus, to understand the possible implications of the hybridization process in the evolutionary history of howler monkeys.Fil: Cortés Ortiz, Liliana. University of Michigan; Estados UnidosFil: Agostini, Ilaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: Aguiar, Lucas M.. Universidade Federal da Integração Latinoamericana; BrasilFil: Kelaita, Mary. University of Texas; Estados UnidosFil: Silva, Felipe Ennes. Instituto de Desenvolvimento Sustentável Mamirauá; BrasilFil: Bicca Marques, Julio Cesar. Pontificia Universidade Catolica Do Rio Grande Do Sul. Facultad de Biociencias; Brasi