32 research outputs found

    Comparison of two sampling protocols and four home-range estimators using radio-tracking data from urban badgers Meles meles

    Get PDF
    Radio-telemetry is often the method of choice for studies of species whose behaviour is difficult to observe directly. However, considerable debate has ensued about the best way of deriving home-range estimates. In recent years, kernel estimators have become the most widely used method, together with the oldest and simplest method, the minimum convex polygon (MCP). More recently, it has been suggested that the local convex hull (LCH) might be more appropriate than kernel methods in cases where an animal’s home range includes a priori inaccessible areas. Yet another method, the Brownian bridge (BB), explicitly uses autocorrelated data to determine movement paths and, ultimately, home ranges or migration routes of animals. Whereas several studies have used simulation techniques to compare these different methods, few have used data from real animals. We used radio-telemetric data from urban badgers Meles meles to compare two sampling protocols (10-minute vs at least 30-minute inter-fix intervals) and four home-range estimators (MCP, fixed kernels (FK), LCH and BB). We used a multi-response permutation procedure and randomisation tests to compare overall patterns of fixes and degree of overlap of home ranges estimated using data from different sampling protocols, and a general linear model to compare the influence of sampling protocols and home-range estimator on the size of habitat patches. The shape of the estimated home ranges was influenced by sampling protocol in some cases. By contrast, the sizes and proportions of different habitats within home ranges were influenced by estimator type but not by sampling protocol. LCH performed consistently better than FK, and is especially appropriate for patchy study areas containing frequent no-go zones. However, we recommend using LCH in combination with other methods to estimate total range size, because LCH tended to produce smaller estimates than any other method. Results relating to BB are preliminary but suggest that this method is unsuitable for species in which range size is small compared to average travel speed.Marie-Curie Intra-European Fellowship (BSSUB - 24007); Defra WSC contract WM0304; Wildlife Biology granted the permit to upload the article to this repositor

    The Evolution of Primate Societies - Chapter 3

    Get PDF
    Compared with other primates, New World monkeys display relatively limited ecological variability. New World monkey anatomy and social systems, however, are extremely diverse. Several unique morphological features (e.g., claws, prehensile tails) and uncommon patterns of social organization (e.g., paternal care, cooperative breeding, female dispersal) have evolved in some platyrrhine species. Social organization and mating patterns include typical harem- like structures where mating is largely polygynous, and large multimale, multifemale groups with promiscuous mating and fi ssion- fusion societies. In addition, some species are socially monogamous and polyandrous. Even closely related species may exhibit strikingly different social organizations, as the example of the squirrel monkeys demonstrates (Mitchell et al. 1991; Boinski et al. 2005b). New World monkey behavior varies within species as well as between them. While the behavior of many species is known from only one study site, intriguing patterns of intraspecific variation are beginning to emerge from observations of populations that sometimes live in close proximity. For example, spider monkeys are often described as showing sex- segregated ranging behavior. Several studies show that males range farther, travel faster, and use larger areas than females, who tend to restrict their habitual ranging to smaller core areas within a group’s large territory (Symington 1988; Chapman 1990; Shimooka 2005). In at least one well- studied population in Yasuní National Park, Ecuador, however, males and females both travel over the entire community home range, and different females within the community show little evidence of occupying distinct core areas (Spehar et al. 2010). Similarly, in most well- studied populations of spider monkeys, females disperse and the resident males within a group are presumed to be close relatives—a suggestion corroborated by genetic data for one local population of spider monkeys in Yasuní. Still, in a different local population, males are not closely related to one another, an unexpected pattern if signifi cant male philopatry were common (Di Fiore 2009; Di Fiore et al. 2009). While the causes of this local variation in group genetic structure are not clear, it may be signifi cant that the groups examined likely had different histories of contact with humans. For longlived animals who occupy relatively small social groups, the loss of even a handful of individuals to hunting, or to any other demographic disturbance, can have a dramatic impact on a group’s genetic structure. Intragroup social relationships, in turn, are likely to be infl uenced by patterns of intragroup relatedness and by the relative availability of social partners of different age or sex class (chapter 21, this volume). Thus, historical and demographic contingencies are likely to create conditions where considerable local, intrapopulation variation in social systems exists. Slight changes in ecological conditions may also contribute to variation in the behavior of individuals living in a single population over time. For example, some authors have hypothesized that howler monkey populations may undergo dramatic fluctuations in size and composition in response to several ecological factors, including resource abundance, parasite and predation pressure, and climate (Milton 1982; Crockett & Eisenberg 1986; Crockett 1996; Milton 1996; Rudran & Fernandez- Duque 2003). This variability, not only among populations, but also within populations across time highlights the need for long- term studies. In sum, our understanding of the behavior of New World monkeys has increased dramatically over the past 25 years. This understanding highlights how their behavior varies within populations over time and among populations or species across space. As our knowledge of platyrrhine behavior continues to unfold and is enriched via additional long- term studies, a central challenge will be to explain how these variations arise. It will be important to entertain adaptive explanations while acknowledging that some differences may emerge via stochastic changes in demography (Struhsaker 2008) or nongenetic, relatively short- term, nonadaptive responses to sudden ecological change

    Of apples and oranges? The evolution of “monogamy” in non-human primates

    Get PDF
    Behavioral ecologists, evolutionary biologists, and anthropologists have been long fascinated by the existence of “monogamy” in the animal kingdom. Multiple studies have explored the factors underlying its evolution and maintenance, sometimes with contradicting and contentious conclusions. These studies have been plagued by a persistent use of fuzzy terminology that often leads to researchers comparing “apples with oranges” (e.g., comparing a grouping pattern or social organization with a sexual or genetic mating system). In this review, we provide an overview of research on “monogamy” in mammals generally and primates in particular, and we discuss a number of problems that complicate comparative attempts to understand this issue. We first highlight why the muddled terminology has hindered our understanding of both a rare social organization and a rare mating system. Then, following a short overview of the main hypotheses explaining the evolution of pair-living and sexualmonogamy, we critically discuss various claims about the principal drivers of “monogamy” that have been made in several recent comparative studies.We stress the importance of using only high quality and comparable data. We then propose that a productive way to frame and dissect the different components of pair-living and sexual or genetic monogamy is by considering the behavioral and evolutionary implications of those components from the perspectives of all participants in a species’ social system. In particular, we highlight the importance of integrating the perspective of “floater” individuals and considering their impacts on local operational sex ratios, competition, and variance in reproductive success across a population. We stress that pair-living need not imply a reduced importance of intrasexual mate competition, a situation that may have implications for the sexual selection potential that have not yet been fully explored. Finally, we note that there is no reason to assume that different taxa and lineages, even within the same radiation, should follow the same pathway to or share a unifying evolutionary explanation for “monogamy”. The study of the evolution of pair-living, sexual monogamy, and genetic monogamy remains a challenging and exciting area of research.Fieldwork related to the data discussed and presented here was supported through grants awarded to AD, EF-D, and their students by the Wenner-Gren Foundation, the L.S.B. Leakey Foundation, the J. William Fulbright Scholar Program, Primate conservation, Inc., Idea Wild, the National Geographic Society, as well by the New York Consortium in Evolutionary Primatology, New York University, the Zoological Society of San Diego, the University of Pennsylvania, the University of Texas at Austin, and Yale University, as well as through grants awarded to Eckhard W. Heyman and MH by the Deutsche Forschungsgesellschaft (HE 1870/10-1,2,3, HU1746-2/1). The Owl Monkey Project of Argentina was supported through the following grants to EFD: NSF-BCS-0621020, 1232349, 1503753 and 1848954; NSF-REU 0837921, 0924352 and 1026991; NSFRAPID-1219368; NIA- P30 AG012836-19, and NICHD R24 HD-044964-11

    The floater's dilemma: use of space by wild solitary Azara's owl monkeys, Aotus azarae , in relation to group ranges

    Get PDF
    The fate and behaviour of animals that leave their natal group (‘floaters’) is usually poorly understood, which can limit the understanding of a species' population dynamics. Attempted immigrations can have serious negative effects on residents who therefore may forcibly reject intruders. Consequently, floaters face a dilemma: they need to leave their natal range to find a breeding territory while trying to avoid potentially lethal rejections from established groups. To examine the hypothesis that floating Azara's owl monkeys avoid established groups temporally, we compared time-matched locations of floaters and groups with randomly selected distances. To examine the hypothesis that floaters avoid established groups spatially, we compared the utilization distribution overlap indices (UDOIs) for core areas of floaters and groups with randomly expected UDOIs. Based on average home range sizes and areas of overlap between floaters, we estimated the floater density in the study area to be 0.2e0.5 per group. The temporal avoidance hypothesis was not supported, since time-matched distances were smaller than distances of random locations, and not larger as predicted under this hypothesis. The spatial avoidance hypothesis, in contrast, was supported, with smaller UDOIs for core ranges than predicted. In conclusion, solitary owl monkeys seem to solve the floater's dilemma by trying to stay in relatively close proximity to groups while still avoiding their core ranges. Floaters thus maximize the number of groups with which they have contact, while being able to leave a group's territory quickly if detected by residents. While no marked sex differences in patterns were detected, there was a strong stochastic element to the number of floaters of a particular sex, thus resulting in a locally uneven operational sex ratio. This, in turn, can have important consequences for various aspects of the population dynamics.The Environmental Sustainability Research Centre of the University of Derby and the Discipline of Biological Sciences provided money for Open Access publication.L.S.B. Leakey Foundation, National Geographic Society and the National Science Foundation of the U.S.A. (NSF-BCS-0621020, 0837921 (REU), 0924352 (REU), 1026991 (REU), 1219368 (RAPID) and 1232349 (2012)

    Relationship between moonlight and nightly activity patterns of the ocelot (Leopardus pardalis) and some of its prey species in Formosa, Northern Argentina

    Get PDF
    The moon can profoundly influence the activity patterns of animals. If predators are more successful under bright moonlight, prey species are likely to respond by shifting their own activity patterns (predator-avoidance hypothesis). However, the assumption that prey will necessarily avoid full-moon nights does not take into account that moonlight also allows prey to more easily detect predators, and to forage more efficiently. Thus, nightly activity patterns could depend on night vision capabilities (visual-acuity hypothesis). To consider the possible influences of moonlight and to distinguish between these hypotheses, we used camera-trapping records of a predator, the ocelot (Leopardus pardalis), and several of its night-active prey to compare activity patterns under different moonlight conditions. The ocelots' activity patterns were not strongly related to moonlight, but showed a slight tendency for higher activity during brighter nights. Tapeti rabbits (Sylvilagus brasiliensis) and brocket deer (Mazama americana) showed a clear preference for brighter nights. White-eared opossums (Didelphis albiventris) also showed a trend to be less active in new moon light. In contrast, smaller grey four-eyed opossums (Philander opossum) and the poor eye-sight nine-banded armadillo (Dasypus novemcinctus) showed similar activity patterns across all moon phases. Since activity patterns of most prey species were not shifted away from the activity of the ocelot, the differences between species are probably linked to their night vision capabilities, and emphasise the need for more information on the visual system of these taxa. Their activity patterns seem to be less strongly linked to avoidance of predation than previously thought, suggesting that foraging and predator detection benefits may play a more important role than usually acknowledged.The cameras were partly funded by a National Geographic Society/Waitt grant to MH (grant number NGS 1072-78) and partly by quality-related funding through the Research Excellence Framework to the Biological Sciences Research Group of the University of Derby. The long-term camera-trap monitoring was in part made possible through grants to EFD and the Owl Monkey Project from the L.S.B. Leakey Foundation, National Geographic Society and the National Science Foundation of the USA (NSF-BCS-0621020, 0837921 (REU), 0924352 (REU), 1026991 (REU), 1219368 (RAPID) and 1232349 (2012)

    The use of animal-borne cameras to video-track the behaviour of domestic cats.

    Get PDF
    Free roaming domestic animals can have a profound effect on wildlife. To better understand and mitigate any impact, it is important to understand the behaviour patterns of the domestic animals, and how other variables might influence their behaviour. Direct observation is not always feasible and bears the potential risk of observer effects. The use of animal-borne small videocameras provides the opportunity to study behaviour from the animal’s point of view. While video-tracking has been used previously to study specific aspects of the behaviour of a species, it has not been used so far to determine detailed time-budgets. The aim of this study was to provide and validate an ethogram based on cat-camera footage collected from 16 cats (Felis catus). The methodology was validated comparing films recorded simultaneously, from both collar-mounted video recorders and hand-held video recorders. Additionally, the inter-observer reliability of scorers was measured. Continuous and instantaneous recording regimes were compared, and behavioural accumulation curves were evaluated to provide further technique recommendations for video-tracking cats. Video-tracking allows scoring of behaviour as reliably as direct observation (linear mixed effects model: t<0.001, P = 0.99; df= 14 in 7 cats; Cohen's Îș =0.88). Furthermore, interobserver reliability was high (Cohen's Îș = 0.72) and was not significantly different from 0.8 (one-sample t-test: t=1.15. df=5, P = 0.30), indicating that the method is not subject to bias in observers. Recommendations are given for the most efficient scoring protocol to reliably record feline behaviour. While the validation was concerned with cat behaviour, the approach can be easily adapted for a variety of domestic species, as well as some captive animals. Video-tracking offers a new avenue to investigate both general time-budgets and more specific behaviours such as foraging or space use from the animal's point of view and in its normal environment, without restrictions to movement. Insights gained through video-tracking will be relevant to various conservation and animal welfare issues.The cameras were funded by research money provided by the University of Derby

    Sexual dimorphism in the loud calls of Azara’s owl monkeys (Aotus azarae): evidence of sexual selection?

    Get PDF
    Primates use different types of vocalizations in a variety of contexts. Some of the most studied types have been the long distance or loud calls. These vocalizations have been associated with mate defense, mate attraction, and resource defense, and it is plausible that sexual selection has played an important role in their evolution. Focusing on identified individuals of known sex and age, we evaluated the sexual dimorphism in a type of loud calls (hoots) in a population of wild owl monkeys (Aotus azarae) in Argentina. We found evidence of sexual dimorphism in call structure, with females and males only emitting one type of call, each differing in dominant frequency and Shannon entropy. In addition, both age-related and sex-specific differences in call usage were also apparent in response to the removal of one group member. Future acoustic data will allow us to assess if there are individual characteristics and if the structure of hoot calls presents differences in relation to the social condition of owl monkeys or specific sex responses to variants of hoot calls’ traits. This will provide deeper insights into the evolution of vocal mechanisms regulating pair bonding and mate choice strategies in this and other primate species.Leakey Foundation, Wenner-Gren Foundation, National Geographic Society, NSF, National Institute on Aging, University of Pennsylvania Research Foundation, Zoological Society of San Dieg

    Preliminary study on the ecology, behaviour and demography of the Bare-faced Curassow (Crax fasciolata) in the gallery forest of the PilagĂĄ River, Formosa, Argentina

    Get PDF
    En Argentina se encuentran seis especies de crĂĄcidos, de las cuales el MuitĂș (Crax fasciolata) es la mĂĄs amenazada y la de distribuciĂłn mĂĄs restringida en el paĂ­s. Debido a que sus principales poblaciones parecen existir a lo largo de los riachos del este formoseño, se trabajĂł en la selva en galerĂ­a del riacho PilagĂĄ en la Estancia Guaycolec para (1) realizar la primera evaluaciĂłn sistemĂĄtica y cuantitativa en Argentina de una poblaciĂłn de MuitĂș, y (2) evaluar la eficacia relativa de muestreos por tierra y agua, cĂĄmaras trampa y emisiĂłn de vocalizaciones grabadas (“playback”) como tĂ©cnicas para el relevamiento poblacional de la especie. Durante 20 dĂ­as se realizaron 22 muestreos en transectas terrestres y 8 en transectas sobre el curso de agua que resultaron en la detecciĂłn de MuitĂș en 22 ocasiones (39 individuos). Las 10 cĂĄmaras trampa generaron 227 fotos de MuitĂș entre octubre de 2010 y julio de 2012 (4007 dĂ­as-cĂĄmara). Tres de las 10 pruebas de emisiĂłn de vocalizaciones resultaron en contacto con un individuo. Los individuos fueron registrados solos o en grupos pequeños de 2–5 individuos, exclusivamente durante el dĂ­a, mĂĄs frecuentemente con temperaturas bajas e intermedias y principalmente en sitios cercanos al riacho. Dada la ausencia de reservas nacionales y provinciales que protejan las selvas en galerĂ­a del este formoseño, resulta imperativo implementar estrategias de conservaciĂłn de la especie que incorporen a las estancias privadas caracterĂ­sticas de la zona.In Argentina there are six species of cracids, the Bare-faced Curassow (Crax fasciolata) being the most endangered and geographically restricted. Given that the main populations of the Barefaced Curassow apparently exist along the rivers of eastern Formosa, the study was conducted in the gallery forests of the PilagĂĄ River in the Guaycolec Ranch to (1) produce the first systematic and quantitative study of a Bare-faced Curassow population in the country, and (2) to evaluate the effectiveness of population assessments conducted through land, water, camera traps, and playbacks as techniques for assessing the population status of the species. During 20 days, 22 assessments were conducted on land and 8 by water, which resulted in the detection of Barefaced Curassow on 22 separate occasions (39 individuals). The camera traps produced 227 pictures of Bare-faced Curassow between October 2010 and July 2012 (4007 camera-days). Contact was made with an individual following 3 of the 10 playback sessions. The Bare-faced Curassow was always sighted as single individuals or in small groups of 2–5 individuals, exclusively during the day, more frequently with low and mild temperatures and in close proximity to the river. Due to the lack of national and provincial areas that can protect the gallery forests of eastern Formosa, it is imperative to develop conservation strategies for the species that consider the private ranches characteristic of the regionFil: FernĂĄndez Duque, Facundo. Universidad Nacional de Formosa; ArgentinaFil: Huck, Maren. University of Derby; Reino UnidoFil: DĂĄvalos, VĂ­ctor. University of Pennsylvania; Estados Unidos. Universidad Nacional de Formosa; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Centro de EcologĂ­a Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de EcologĂ­a Aplicada del Litoral; ArgentinaFil: Fernandez Duque, Eduardo. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Nordeste. Centro de Ecologia Aplicada del Litoral (i); Argentina. Universidad Nacional de Formosa; Argentina. University of Pennsylvania; Estados Unido

    First craneal evidence and documented occurrence of Cuniculus paca (Rodentia, Cuniculidae) for the Humid Chaco region of Argentina

    Get PDF
    Se reporta el primer registro con material de referencia de Cuniculus paca para la provincia de Formosa en la RegiĂłn Chaqueña Argentina. Este se basa en un crĂĄneo colectado y en 18 fotografĂ­as obtenidas con trampas cĂĄmaras en la selva en galerĂ­a del riacho PilagĂĄ (estancia Guaycolec: 25° 58’ S, 58° 11’ O) ubicada en la macrounidad ambiental del Chaco HĂșmedo. Se caracterizĂł el patrĂłn de actividad de la especie a partir de los registros horarios de las fotografĂ­as. Se observĂł un patrĂłn de actividad estrictamente nocturno, aparentemente influenciado por el ciclo lunar; no se obtuvo ningĂșn registro fotogrĂĄfico durante perĂ­odos de luna llena o luna nueva. Todas las fotos fueron obtenidas a una distancia mĂĄxima de 170 m del rĂ­o, indicando una fuerte asociaciĂłn de la especie con los cursos de aguaWe report the first record of Cuniculus paca for the province of Formosa in Argentina and the Argentinean Gran Chaco region based on one skull found close to the river PilagĂĄ (estancia Guaycolec: 25° 58’ S, 58° 11’ W) and on 18 photos taken by camera traps. Since the photos include time-stamps, we were able to evaluate the activity pattern of the paca in that area. Pacas showed strict nocturnal behavior and seemed to be influenced by the lunar cycles; there were no records during full and new moon. All photos were taken at a maximum distance of 170 m to the river, confirming the strong association of the species to watercourses.Fil: Huck, Maren. Deutsches Primatenzentrum; AlemaniaFil: JuĂĄrez, Cecilia Paola. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Centro de EcologĂ­a Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de EcologĂ­a Aplicada del Litoral; Argentina. Barrio General JosĂ© de San MartĂ­n. Proyecto MirikinĂĄ; ArgentinaFil: Rotundo, Marcelo A.. Barrio General JosĂ© de San MartĂ­n. Proyecto MirikinĂĄ; ArgentinaFil: Fernandez Duque, Eduardo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Barrio General JosĂ© de San MartĂ­n. Proyecto MirikinĂĄ; Argentina. University of Pennsylvania; Estados Unido
    corecore