Ecological consequences of individual spatial choice in foraging groups of brown capuchin monkeys, Cebus apella
Animal Behaviour, 1990
... choice of juveniles is suggested by the fact that olderinfants stay in the back-centre of the... more ... choice of juveniles is suggested by the fact that olderinfants stay in the back-centre of the group (where vigi-lance is lowest ... I expect that the development of group spatial structure will correlate with the importance ofwithin-group aggressive compe-tition (Janson van Schaik 1988 ...
I focus on the foraging efficiency (food intake per time) of a hypothetical forager that uses dis... more I focus on the foraging efficiency (food intake per time) of a hypothetical forager that uses distinct levels of information about a set of discrete renewing resources. The information may be the distance to the resource (D), both distance and maximum productivity of the resource (DP), or distance, productivity, and the elapsed time since the forager last visited each resource (DPT). The expected foraging efficiencies are based on the results of a field experiment on wild capuchin monkeys (Janson, 2016a) that documented the use of integrative memories of resource location, productivity, and elapsed time since the previous visit. Computer simulations of the choice process are used to extend the resource parameter space beyond the field experiment. The goal is to explore to what extent the use of elapsed time in choosing discrete feeding sites is a benefit under various conditions of resource and consumer characteristics. Major findings include that the use of elapsed time generally increases foraging efficiency on renewing resources by 30-35%, without much effect of resource size or variability-indeed, DPT outperforms D or DP choice even when all resources have the same productivity. The relative benefit of DPT increases when the most productive resources are only moderately common (not so rare that they contribute little to food intake, nor so common that choosing the nearest resource is likely to arrive at a highly productive one). The relative benefit of DPT decreases when the forager's gut capacity is small or gut passage time is long because it cannot ingest all of the resource accumulated after long elapsed intervals. I suggest that memory for and use of elapsed intervals since prior visits in foraging choices will prove to be a common feature of diverse foraging animals whenever the presence of a forager depresses food availability in a local area.
Large vertebrates are important elements of mutualistic interactions and provide positive impacts... more Large vertebrates are important elements of mutualistic interactions and provide positive impacts on plant population and community dynamics. Despite the increasing interest on vertebrate frugivory we are still not able to disentangle the real contribution of seed dispersal to Neotropical forest functioning. Consuming fruits does not imply effective seed dispersal and many variables, such as seed size and animal diet, may influence the outcome of plant-animal interactions. Here, we performed a comprehensive literature search on seed dispersal by Neotropical vertebrates (with a focus on primates) to closely approach their role as seed dispersers, hypothesizing frugivory degree and seed size as main drivers of fruit handling behavior and diversity of dispersed seeds. We found that the great majority of seeds manipulated by Neotropical primates, with exception to the seed predators pitheciins, were swallowed and passed intact through their gut. Larger seeds (> 12 mm) tended of being ingested exclusively by primates and other large vertebrates, such as tapirs and peccaries. Furthermore, primate feeding guild had a great influence on the richness and sizes of seeds dispersed, as primarily frugivores dispersed more species and had higher probabilities of ingesting larger seeds when compared to other feeding guilds. Organizing available knowledge and filling the main knowledge gaps allowed us to validate common sense assumptions and ultimately draw new conclusions about the role played by primates together with other major frugivores in Neotropical forests.
Seed dispersal distance (SDD) is a vital component of vertebrate-mediated seed dispersal process:... more Seed dispersal distance (SDD) is a vital component of vertebrate-mediated seed dispersal process: the average distance at which seeds are deposited away from the parent plant represents the starting template of plant regeneration. We present a simple model to explain and predict observed measures of average dispersal distance and we hypothesize that it is a consequence of how long seeds are retained in the disperser's gut, how rapidly the disperser moves per unit time and how twisted the animal travel path is relative to the straight-line distance moved away from the seed source. We retrieved data on dispersal distances from 26 published studies including nine primate species dispersing up to 112 plant species per study. We used gut transit time (TT) as a proxy for residence time inside the gut, the disperser's travel path per hour as proxy for movement rate, and the daily path length relative to the home range area as a correlate of path twisting (PT). We illustrate this model with comparative data on Neotropical primates. These three variables explained 90% of the variation in the average SDD. Path analysis indicates that additional variables exerted only indirect effects. Our model can be applied to primate populations for which detailed seed dispersal data are missing, and help evaluate conservation priorities for primate species according to the potential service they provide in terms of forest regeneration.
There is considerable controversy about the existence, extent and adaptive value of integrated mu... more There is considerable controversy about the existence, extent and adaptive value of integrated multimodal memory in non-human animals. Building on prior results showing that wild capuchin monkeys in Argentina appear to recall both the location and amount of food at patches they had previously visited, I tested whether they also track and use elapsed time as a basis for decisions about which feeding patches to visit. I presented them with an experimental array of eight feeding sites, at each of which food rewards increased with increasing elapsed time since the previous visit, similar to the pattern of ripe fruit accumulation in natural feeding trees. Over the course of 68 days, comprising two distinct renewal rate treatments, one group repeatedly visited sites in the feeding array, generating 212 valid choices between sites. Comparison of observations against simulated movements and multinomial statistical models shows that the monkeys' choices were most consistent with dynamic ...
Aim Capuchin monkey species are widely distributed across Central and South America. Morphologica... more Aim Capuchin monkey species are widely distributed across Central and South America. Morphological studies consistently divide the clade into robust and gracile forms, which show extensive sympatry in the Amazon Basin. We use genetic data to test whether Miocene or Plio-Pleistocene processes may explain capuchin species' present distributions, and consider three possible scenarios to explain widespread sympatry. Location The Neotropics, including the Amazon and Atlantic Coastal Forest. Methods We sequenced the 12S ribosomal RNA and cytochrome b genes from capuchin monkey specimens. The majority were sampled from US museum collections and were wild-caught individuals of known provenance across their distribution. We applied a Bayesian discrete-states diffusion model, which reconstructed the most probable history of invasion across nine subregions. We used comparative methods to test for phylogeographic association and dispersal rate variation. Results Capuchins contained two well supported monophyletic clades, the morphologically distinct 'gracile' and 'robust' groups. The time-tree analysis estimated a late Miocene divergence between Cebus and Sapajus and a subsequent Plio-Pleistocene diversification within each of the two clades. Bayesian analysis of phylogeographic diffusion history indicated that the current wide-ranging sympatry of Cebus and Sapajus across much of the Amazon Basin was the result of a single explosive late Pleistocene invasion of Sapajus from the Atlantic Forest into the Amazon, where Sapajus is now sympatric with gracile capuchins across much of their range. Main conclusions The biogeographic history of capuchins suggests late Miocene geographic isolation of the gracile and robust forms. Each form diversified independently, but during the Pleistocene, the robust Sapajus expanded its range from the Atlantic Forest to the Amazon, where it has now encroached substantially upon what was previously the exclusive range of gracile Cebus. The genus Cebus, as currently recognized, should be split into two genera to reflect the Miocene divergence and two subsequent independent Pliocene radiations: Cebus from the Amazon and Sapajus from the Atlantic Forest.
Judgment under uncertainty: Evolution may not favor a probabilistic calculus
Behavioral and Brain Sciences, 1996
The environment in which humans evolved is strongly and positively autocorrelated in space and ti... more The environment in which humans evolved is strongly and positively autocorrelated in space and time. Probabilistic judgments based on the assumption of independence may not yield evolutionarily adaptive behavior. A number of “faults” of human reasoning are not faulty under fuzzy arithmetic, a nonprobabilistic calculus of reasoning under uncertainty that may be closer to that underlying human decision making.
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights
Social correlates of individual spatial choice in foraging groups of brown capuchin monkeys, Cebus apella
Animal Behaviour, 1990
... Juvenilesappear to be further back in the group than adults of similar social status, but the... more ... Juvenilesappear to be further back in the group than adults of similar social status, but the difference is not significant (F= 2.54,df= 1,9, P = 0.146).Seasonal Variation in Positional Behaviour Individuals changed positional behaviour in dif-ferent seasonal samples (test forno ...
The Editor-in-Chief of Primates thanks the following personnel as well as the members of the Editorial Board and Advisory Board for their editorial help during the past year (July 2010–June 2011). An asterisk indicates consultation on two or more manuscripts
Primates, 2011
The Editor-in-Chief of Primates thanks the following personnel as well as the members of the Edit... more The Editor-in-Chief of Primates thanks the following personnel as well as the members of the Editorial Board and Advisory Board for their editorial help during the past year (July 2010–June 2011). An asterisk indicates consultation on two or more manuscripts. ... Adachi, Ikuma, Kyoto University Agetsuma, Naoki*, Hokkaido University Albuquerque, George R., Universidade Estadual de Santa Cruz Aureli, Filipo*, Liverpool John Moores University Barelli, Claudia, Museo Tridentino di Scienze Naturali Bartlett, Thad Q.*, University of Texas at San Antonio Bercovitch, Fred ...
The frequency of anointing bouts and the materials used for self-and social anointing vary across... more The frequency of anointing bouts and the materials used for self-and social anointing vary across capuchin species in captivity, but there is little published data on capuchin anointing in the wild. Here we present previously unpublished data on anointing behaviors from capuchin monkey populations at ten different field sites and incorporate these data into a review of the anointing literature for captive and wild capuchins. Using a comparative phylogenetic framework, we test four hypotheses derived primarily from captive literature for variation in anointing between wild untufted capuchins (Cebus) and tufted capuchins (Sapajus), including that (1) the frequency of anointing is higher in Cebus, (2) Cebus uses a higher proportion of plant species to insect species for anointing compared with Sapajus, (3) anointing material diversity is higher in Cebus, and (4) social indices of anointing are higher in Cebus. We found that wild Cebus anoints more with plant parts, including fruits, whereas wild Sapajus anoints more with ants and other arthropods. Cebus capucinus in particular uses more plant species per site for anointing compared with other capuchins and may specialize in anointing as an activity independent from foraging, whereas most other capuchin species tend to eat the substances they use for anointing. In agreement with captive studies, we found evidence that wild Cebus anoints at a significantly higher frequency than Sapajus. However, contrary to the captive literature, we found no difference in the range of sociality for anointing between Cebus and Sapajus in the wild. We review anointing in the context of other Neotropical primate rubbing behaviors and consider the evidence for anointing as self-medication; as a mechanism for enhanced sociality; and as a behavioral response to
Female Choice and Mating System of the Brown Capuchin Monkey Cebus apella (Primates: Cebidae)
Zeitschrift für Tierpsychologie, 1984
Female choice and mating system of the brown capuchin monkey Cebus apella(Primates: Cebidae). CH ... more Female choice and mating system of the brown capuchin monkey Cebus apella(Primates: Cebidae). CH JANSON Zeitschrift für Tierpsychologie ...
Predicting group size in primates: foraging costs and predation risks
Behavioral Ecology, 1995
... Charles H. Janson* and Michele L. Goldsmith* 'Department of Ecology and Evolutio... more ... Charles H. Janson* and Michele L. Goldsmith* 'Department of Ecology and Evolution and bDepartment of Anthropology, State University of New York ... Rowell, 1988; (r) Butynski, 1990; (s) Struhsaker and Leland, 1988; (t) Whitesides, 1989; (u) Waser, 1977; (v) Sigg and Stolba ...
Book Review:Adaptations for Foraging in Nonhuman Primates. Contributions to an Organismal Biology of Prosimians, Monkeys, And Apes. Peter S. Rodman, John G. H. Cant
This textbook, which is intended for undergraduates, provides a comprehensive summary of the lite... more This textbook, which is intended for undergraduates, provides a comprehensive summary of the literature relating to the ecology and evolution of animal and plant interactions. The 10 chapters are grouped into 4 main sections ...
Ecological consequences of individual spatial choice in foraging groups of brown capuchin monkeys, Cebus apella
Animal Behaviour, 1990
... choice of juveniles is suggested by the fact that olderinfants stay in the back-centre of the... more ... choice of juveniles is suggested by the fact that olderinfants stay in the back-centre of the group (where vigi-lance is lowest ... I expect that the development of group spatial structure will correlate with the importance ofwithin-group aggressive compe-tition (Janson van Schaik 1988 ...
I focus on the foraging efficiency (food intake per time) of a hypothetical forager that uses dis... more I focus on the foraging efficiency (food intake per time) of a hypothetical forager that uses distinct levels of information about a set of discrete renewing resources. The information may be the distance to the resource (D), both distance and maximum productivity of the resource (DP), or distance, productivity, and the elapsed time since the forager last visited each resource (DPT). The expected foraging efficiencies are based on the results of a field experiment on wild capuchin monkeys (Janson, 2016a) that documented the use of integrative memories of resource location, productivity, and elapsed time since the previous visit. Computer simulations of the choice process are used to extend the resource parameter space beyond the field experiment. The goal is to explore to what extent the use of elapsed time in choosing discrete feeding sites is a benefit under various conditions of resource and consumer characteristics. Major findings include that the use of elapsed time generally increases foraging efficiency on renewing resources by 30-35%, without much effect of resource size or variability-indeed, DPT outperforms D or DP choice even when all resources have the same productivity. The relative benefit of DPT increases when the most productive resources are only moderately common (not so rare that they contribute little to food intake, nor so common that choosing the nearest resource is likely to arrive at a highly productive one). The relative benefit of DPT decreases when the forager's gut capacity is small or gut passage time is long because it cannot ingest all of the resource accumulated after long elapsed intervals. I suggest that memory for and use of elapsed intervals since prior visits in foraging choices will prove to be a common feature of diverse foraging animals whenever the presence of a forager depresses food availability in a local area.
Large vertebrates are important elements of mutualistic interactions and provide positive impacts... more Large vertebrates are important elements of mutualistic interactions and provide positive impacts on plant population and community dynamics. Despite the increasing interest on vertebrate frugivory we are still not able to disentangle the real contribution of seed dispersal to Neotropical forest functioning. Consuming fruits does not imply effective seed dispersal and many variables, such as seed size and animal diet, may influence the outcome of plant-animal interactions. Here, we performed a comprehensive literature search on seed dispersal by Neotropical vertebrates (with a focus on primates) to closely approach their role as seed dispersers, hypothesizing frugivory degree and seed size as main drivers of fruit handling behavior and diversity of dispersed seeds. We found that the great majority of seeds manipulated by Neotropical primates, with exception to the seed predators pitheciins, were swallowed and passed intact through their gut. Larger seeds (> 12 mm) tended of being ingested exclusively by primates and other large vertebrates, such as tapirs and peccaries. Furthermore, primate feeding guild had a great influence on the richness and sizes of seeds dispersed, as primarily frugivores dispersed more species and had higher probabilities of ingesting larger seeds when compared to other feeding guilds. Organizing available knowledge and filling the main knowledge gaps allowed us to validate common sense assumptions and ultimately draw new conclusions about the role played by primates together with other major frugivores in Neotropical forests.
Seed dispersal distance (SDD) is a vital component of vertebrate-mediated seed dispersal process:... more Seed dispersal distance (SDD) is a vital component of vertebrate-mediated seed dispersal process: the average distance at which seeds are deposited away from the parent plant represents the starting template of plant regeneration. We present a simple model to explain and predict observed measures of average dispersal distance and we hypothesize that it is a consequence of how long seeds are retained in the disperser's gut, how rapidly the disperser moves per unit time and how twisted the animal travel path is relative to the straight-line distance moved away from the seed source. We retrieved data on dispersal distances from 26 published studies including nine primate species dispersing up to 112 plant species per study. We used gut transit time (TT) as a proxy for residence time inside the gut, the disperser's travel path per hour as proxy for movement rate, and the daily path length relative to the home range area as a correlate of path twisting (PT). We illustrate this model with comparative data on Neotropical primates. These three variables explained 90% of the variation in the average SDD. Path analysis indicates that additional variables exerted only indirect effects. Our model can be applied to primate populations for which detailed seed dispersal data are missing, and help evaluate conservation priorities for primate species according to the potential service they provide in terms of forest regeneration.
There is considerable controversy about the existence, extent and adaptive value of integrated mu... more There is considerable controversy about the existence, extent and adaptive value of integrated multimodal memory in non-human animals. Building on prior results showing that wild capuchin monkeys in Argentina appear to recall both the location and amount of food at patches they had previously visited, I tested whether they also track and use elapsed time as a basis for decisions about which feeding patches to visit. I presented them with an experimental array of eight feeding sites, at each of which food rewards increased with increasing elapsed time since the previous visit, similar to the pattern of ripe fruit accumulation in natural feeding trees. Over the course of 68 days, comprising two distinct renewal rate treatments, one group repeatedly visited sites in the feeding array, generating 212 valid choices between sites. Comparison of observations against simulated movements and multinomial statistical models shows that the monkeys' choices were most consistent with dynamic ...
Aim Capuchin monkey species are widely distributed across Central and South America. Morphologica... more Aim Capuchin monkey species are widely distributed across Central and South America. Morphological studies consistently divide the clade into robust and gracile forms, which show extensive sympatry in the Amazon Basin. We use genetic data to test whether Miocene or Plio-Pleistocene processes may explain capuchin species' present distributions, and consider three possible scenarios to explain widespread sympatry. Location The Neotropics, including the Amazon and Atlantic Coastal Forest. Methods We sequenced the 12S ribosomal RNA and cytochrome b genes from capuchin monkey specimens. The majority were sampled from US museum collections and were wild-caught individuals of known provenance across their distribution. We applied a Bayesian discrete-states diffusion model, which reconstructed the most probable history of invasion across nine subregions. We used comparative methods to test for phylogeographic association and dispersal rate variation. Results Capuchins contained two well supported monophyletic clades, the morphologically distinct 'gracile' and 'robust' groups. The time-tree analysis estimated a late Miocene divergence between Cebus and Sapajus and a subsequent Plio-Pleistocene diversification within each of the two clades. Bayesian analysis of phylogeographic diffusion history indicated that the current wide-ranging sympatry of Cebus and Sapajus across much of the Amazon Basin was the result of a single explosive late Pleistocene invasion of Sapajus from the Atlantic Forest into the Amazon, where Sapajus is now sympatric with gracile capuchins across much of their range. Main conclusions The biogeographic history of capuchins suggests late Miocene geographic isolation of the gracile and robust forms. Each form diversified independently, but during the Pleistocene, the robust Sapajus expanded its range from the Atlantic Forest to the Amazon, where it has now encroached substantially upon what was previously the exclusive range of gracile Cebus. The genus Cebus, as currently recognized, should be split into two genera to reflect the Miocene divergence and two subsequent independent Pliocene radiations: Cebus from the Amazon and Sapajus from the Atlantic Forest.
Judgment under uncertainty: Evolution may not favor a probabilistic calculus
Behavioral and Brain Sciences, 1996
The environment in which humans evolved is strongly and positively autocorrelated in space and ti... more The environment in which humans evolved is strongly and positively autocorrelated in space and time. Probabilistic judgments based on the assumption of independence may not yield evolutionarily adaptive behavior. A number of “faults” of human reasoning are not faulty under fuzzy arithmetic, a nonprobabilistic calculus of reasoning under uncertainty that may be closer to that underlying human decision making.
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights
Social correlates of individual spatial choice in foraging groups of brown capuchin monkeys, Cebus apella
Animal Behaviour, 1990
... Juvenilesappear to be further back in the group than adults of similar social status, but the... more ... Juvenilesappear to be further back in the group than adults of similar social status, but the difference is not significant (F= 2.54,df= 1,9, P = 0.146).Seasonal Variation in Positional Behaviour Individuals changed positional behaviour in dif-ferent seasonal samples (test forno ...
The Editor-in-Chief of Primates thanks the following personnel as well as the members of the Editorial Board and Advisory Board for their editorial help during the past year (July 2010–June 2011). An asterisk indicates consultation on two or more manuscripts
Primates, 2011
The Editor-in-Chief of Primates thanks the following personnel as well as the members of the Edit... more The Editor-in-Chief of Primates thanks the following personnel as well as the members of the Editorial Board and Advisory Board for their editorial help during the past year (July 2010–June 2011). An asterisk indicates consultation on two or more manuscripts. ... Adachi, Ikuma, Kyoto University Agetsuma, Naoki*, Hokkaido University Albuquerque, George R., Universidade Estadual de Santa Cruz Aureli, Filipo*, Liverpool John Moores University Barelli, Claudia, Museo Tridentino di Scienze Naturali Bartlett, Thad Q.*, University of Texas at San Antonio Bercovitch, Fred ...
The frequency of anointing bouts and the materials used for self-and social anointing vary across... more The frequency of anointing bouts and the materials used for self-and social anointing vary across capuchin species in captivity, but there is little published data on capuchin anointing in the wild. Here we present previously unpublished data on anointing behaviors from capuchin monkey populations at ten different field sites and incorporate these data into a review of the anointing literature for captive and wild capuchins. Using a comparative phylogenetic framework, we test four hypotheses derived primarily from captive literature for variation in anointing between wild untufted capuchins (Cebus) and tufted capuchins (Sapajus), including that (1) the frequency of anointing is higher in Cebus, (2) Cebus uses a higher proportion of plant species to insect species for anointing compared with Sapajus, (3) anointing material diversity is higher in Cebus, and (4) social indices of anointing are higher in Cebus. We found that wild Cebus anoints more with plant parts, including fruits, whereas wild Sapajus anoints more with ants and other arthropods. Cebus capucinus in particular uses more plant species per site for anointing compared with other capuchins and may specialize in anointing as an activity independent from foraging, whereas most other capuchin species tend to eat the substances they use for anointing. In agreement with captive studies, we found evidence that wild Cebus anoints at a significantly higher frequency than Sapajus. However, contrary to the captive literature, we found no difference in the range of sociality for anointing between Cebus and Sapajus in the wild. We review anointing in the context of other Neotropical primate rubbing behaviors and consider the evidence for anointing as self-medication; as a mechanism for enhanced sociality; and as a behavioral response to
Female Choice and Mating System of the Brown Capuchin Monkey Cebus apella (Primates: Cebidae)
Zeitschrift für Tierpsychologie, 1984
Female choice and mating system of the brown capuchin monkey Cebus apella(Primates: Cebidae). CH ... more Female choice and mating system of the brown capuchin monkey Cebus apella(Primates: Cebidae). CH JANSON Zeitschrift für Tierpsychologie ...
Predicting group size in primates: foraging costs and predation risks
Behavioral Ecology, 1995
... Charles H. Janson* and Michele L. Goldsmith* 'Department of Ecology and Evolutio... more ... Charles H. Janson* and Michele L. Goldsmith* 'Department of Ecology and Evolution and bDepartment of Anthropology, State University of New York ... Rowell, 1988; (r) Butynski, 1990; (s) Struhsaker and Leland, 1988; (t) Whitesides, 1989; (u) Waser, 1977; (v) Sigg and Stolba ...
Book Review:Adaptations for Foraging in Nonhuman Primates. Contributions to an Organismal Biology of Prosimians, Monkeys, And Apes. Peter S. Rodman, John G. H. Cant
This textbook, which is intended for undergraduates, provides a comprehensive summary of the lite... more This textbook, which is intended for undergraduates, provides a comprehensive summary of the literature relating to the ecology and evolution of animal and plant interactions. The 10 chapters are grouped into 4 main sections ...
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