Norberto Asensio

• PhD Animal Behaviour
• Professor (Assistant) at University of the Basque Country

Gibbons (Hylobatidae) are species highly adapted to tree-top living. Thus, their movement can be compromised due to the negative impact roads have on canopy habitats. In this study, we built two single-rope artificial canopy bridges and a ladder bridge at two out of five locations where a group of white-handed gibbons ( Hylobates lar ) in Khao Yai...

The study of animal play is highly complex since its potential functions vary with social and environmental circumstances. Although play is generally characteristic of immature animals, it may persist in adults in its social form, particularly when interacting with young individuals, and less often with other adult playmates. We measured the amount...

Natural hybridization has played various roles in the evolutionary history of primates. Its consequences range from genetic introgression between taxa, formation of hybrid zones, and formation of new lineages. Hylobates lar, the white-handed gibbon, and Hylobates pileatus, the pileated gibbon, are largely allopatric species in Southeast Asia with a...

The unavoidable impact of roads on arboreal fauna in protected areas has received little attention. We investigated this impact on two gibbon species in Khao Yai National Park, Thailand: two groups had home ranges traversed by roads (roadside groups) and another two lived nearby roads (interior groups). Roads partially delineated the edges of home...

Limestone karst habitats are threatened globally by quarrying for production of concrete and cement. A significant area of limestone karst shared among the provinces of Saraburi, Lopburi and Nakhon Ratchasima in Thailand encompasses the entire global range of a threatened bird taxon, the Rufous Limestone Babbler Gypsophila calcicola. We estimate th...

Research on non‐human primates in the endangered tropical dry forest of Sector Santa Rosa (SSR), Área de Conservación Guanacaste (ACG), was launched in 1983 and is now one of the longest running studies of primates globally. Such continuous study provides a rare opportunity to ask questions that are only answerable through decades‐long monitoring o...

Fragmented tropical forests can be highly dynamic, with the spatial configuration of forest patches changing through time. Yet, the lack of longitudinal studies limits our understanding of how patch dynamics affect biodiversity, especially when there is a time lag in species extinctions (extinction debt). We assessed how temporal changes in patch s...

All gibbon species are declining throughout South and South-east Asia because of habitat loss and human activities such as hunting. Lao still contains a relatively large area of forest habitat suitable for gibbons, but their status in the country remains poorly known. Here we present the first density estimate of the Critically Endangered northern...

Range defensibility is defined as the ability of animals to efficiently move over an area to monitor and defend it. Therefore, range defensibility can help us understand the spatial structure of animal territoriality. We used howler monkeys (Alouatta spp.), a genus for which no agreement on the extent of their territoriality exists, to investigate...

Objectives: The study of related species in contact zones can elucidate what factors mediate species coexistence and geographical distributions. We investigated niche overlap and group interactions of two gibbon species and their hybrids co-occurring in a zone of overlap and hybridization. Methods: The location, composition and behavior of white...

Arboreal fauna living in tropical ecosystems may be particularly affected by roads given their dependency on forest cover and the high vulnerability of such ecosystems to changes. Over a period of 4 yr, we followed subgroups of spider monkeys living in a regenerating dry tropical forest with 8.2 km of roads within their home range. We aimed to unde...

Information derived from long-term monitoring at the community level is essential to the effective management of wild mammal populations. However, this information is scarce and cannot be generated soon enough to address the needs of immediate management planning. In this study we measure long-term changes in the richness and abundance of a large-...

Understanding the way howler monkeys interact with other vertebrates has critical ecological, evolutionary, cognitive, and conservation implications. In this review, we completed an extensive search of the available data on interspecific howler encounters, including individual communications from field primatologists, in order to gain insight into...

Human food supplementation can affect components of animal socioecology by altering the abundance and distribution of available food. We studied the effect of food supplementation by comparing the ranging patterns and intergroup interactions of two groups of northern pigtailed macaques (Macaca leonina), a non-territorial primate species. One group...

Sleeping site selection in nonhuman primates may respond to various ecological factors, including predation avoidance, range defense, and foraging efficiency. We studied the sleeping sites used by a group of northern pigtailed macaques on 124 nights to test these hypotheses. The macaques used 57 different sleeping sites, of which 33 were used only...

Space-use patterns are crucial to understanding the ecology, evolution, and conservation of primates, but detailed ranging data are scarce for many species, especially those in Southeast Asia. Researchers studying site fidelity to either home ranges or core areas have focused mainly on territorial species, whereas less information is available for...

In species with a high degree of fission-fusion dynamics group members may differ in the use of the group home range to reduce food competition. Such differential use may result in distinct individual core areas. We studied core area quality and overlap among 21 female spider monkeys belonging to the same group over a period of 4 years. Core areas...

We studied the temporal and spatial patterns of leptospirosis, its association with flooding and animal census data in Thailand. Flood data from 2010 to 2012 were extracted from spatial information taken from satellite images. The incidence rate ratio (IRR) was used to determine the relationship between spatio-temporal flooding patterns and the num...

Lianas are becoming an increasingly prominent component of tropical forests. This chapter evaluates the use of lianas by primates an abundant, species-rich, and ecologically important order of mammals. The great majority of primate species are highly arboreal, and they depend on the different strata above the forest floor for feeding, traveling, re...

Core areas represent small regions within animal home-ranges intensively used during a given period of time. We assessed the quality of core areas relative to the rest of the home-ranges (i.e., non-core areas) of 11 groups of the territorial and highly frugivorous white-handed gibbon (Hylobates lar) over a short-time scale to reflect temporarily av...

Desde tiempos remotos los humanos han observado el comportamiento animal, primero para sobrevivir, luego para cazarlos y después para domesticarlos. Hoy en día, en el mundo natural y urbano en el que vivimos ¿quién no ha visto un ave alzar sus coloridas alas y aletearlas vigorosamente hacia una hembra, o a una ardilla comiendo semillas? Por un moti...

La etología considera los comportamientos como adaptaciones biológicas efectivas en el contexto del animal que los lleva a cabo. En algunos casos, comprender estas adaptaciones resulta complicado, en especial cuando un único comportamiento puede servir para el mismo propósito en diferentes situaciones. El juego presenta esta complicación y, por est...

Fission–fusion dynamics derive from spatial adjustments that animals make depending on resource distribution, resulting in splitting and merging of subgroups. New frameworks propose to classify social systems depending on their degree of fission–fusion dynamics, but little has been done to quantify such dynamics. Operationally defining subgroup is...

Core areas are thought to be critical parts of animal home ranges for sustaining the population, but few studies have tested this important assumption. We examined whether core areas of spider monkeys Ateles geoffroyi had better habitat quality than the rest of their home range (non‐core areas). Habitat quality parameters, including density and div...

Lianas are important components in the dynamics of tropical forests and represent fallback foods for some primates, yet little is known about their impact on primate ecology, behavior or fitness. Using 2 yr of field data, we investigated liana consumption and foraging effort in four groups of howler monkeys (two in bigger, more conserved forest fra...

Core areas are highly used parts of the home range on which the survival of solitary or group-living animals depends. We investigated the home range and core area size and area fidelity of a spider monkey community in a tropical dry forest over a 4-year period. Home ranges overlapped extensively across years, subgroup sizes, and seasons. In contras...

Remembering locations of food resources is critical for animal survival. Gibbons are territorial primates which regularly travel through small and stable home ranges in search of preferred, limited and patchily distributed resources (primarily ripe fruit). They are predicted to profit from an ability to memorize the spatial characteristics of their...

Many animal populations are forced to inhabit very small forest patches, which may threaten their long-term survival. In some cases, animals in these forest remnants are able to supplement their diet by using resources outside of their home patch, a process named ‘landscape supplementation’. Although this is probably a key process for population su...

The adjustment to deal with intragroup food competition is probably the most plausible explanation of high levels of fission–fusion dynamics. However, studies did not always support expected relations between food availability, ranging costs, and subgroup size. We used several levels of analysis differing in the time and spatial scale in order to i...

Scramble competition is related to animals depleting resources before others can use them, whereas contest competition is associated with the monopolization of resources and food-related aggression. One hypothesized major benefit of fission-fusion sociality is the reduction of scramble feeding competition between community members. We studied intra...

This paper represents the results of a long-term study (1996-2003) on the demographic changes over time of a Mexican mantled howler (Alouatta palliata mexicana) group in a rainforest fragment (40 ha) in Los Tuxtlas, Mexico, with a follow-up census 3 years later (2006). In addition to demographic and life history parameters, we describe six dispersa...

Interactions between sympatric species are of particular interest for understanding the mechanisms that allow animal coexistence in the ecological community. The mantled howler monkey ( Alouatta palliata Gray) and the white-nosed coati ( Nasua narica Linnaeus) are similar-sized mammals with a sympatric distribution in the Neotropics (Nowak 1999). S...

The activity patterns and diet of howler monkeys (Alouatta palliata mexicana) were studied in 3 forest fragments in south-eastern Mexico: Playa Escondida (PLA), Agaltepec Island (AGA) and Arroyo Liza (LIZ). Intersite differences offered the opportunity to investigate the foraging adaptations of howler monkeys in response to population and habitat s...

This research focuses on identifying the principal habitat characteristics that influence the presence and abundance of mantled howlers in forest fragments. We provide information on the demography of several fragmented Alouatta palliata mexicana subpopulations at Los Tuxtlas, Mexico, and relate this to the biogeographical and floristic characteris...

This paper reports the response of one howler monkey group (Alouatta palliata) to a group of potential predators, the tayra (Eira barbara). The apparently successful predator avoidance behavior of the monkeys was recorded in detail. We observed a group of four adult tayras moving around the Alouatta group displaying a species-typical aggressive beh...

Tesis doctoral inédita leida en la Universidad Autónoma de Madrid, Facultad de Psicología, Departamento de Psicología Biológica y de la Salud. Fecha de lectura : 10 de julio de 2003 Bibliogr.: p. 151-170