scholarly journals Where and what? Frugivory is associated with more efficient foraging in three semi-free ranging primate species

2019 ◽  
Vol 6 (5) ◽  
pp. 181722 ◽  
Author(s):  
Cinzia Trapanese ◽  
Benjamin Robira ◽  
Giordana Tonachella ◽  
Silvia di Gristina ◽  
Hélène Meunier ◽  
...  
Keyword(s):  
Comparative Studies ◽  
Brain Size ◽  
Primate Species ◽  
Food Type ◽  
Foraging Efficiency ◽  
Macaca Tonkeana ◽  
Foraging Decisions ◽  
Sapajus Apella ◽  
Spatio Temporal ◽  
Free Ranging

Foraging in seasonal environments can be cognitively challenging. Comparative studies have associated brain size with a frugivorous diet. We investigated how fruit distribution ( where ) and preference ( what ) affect foraging decisions in three semi-free ranging primate species with different degrees of frugivory: Macaca tonkeana ( N indiv = 5; N trials = 430), M. fascicularis ( N indiv = 3; N trials = 168) and Sapajus apella ( N indiv = 6; N trials = 288). We used 36 boxes fixed on trees and filled with highly and less preferred fruits with different (weekly) spatio-temporal distributions. Individuals were tested in two conditions: (1) same fruit provided concurrently in the same quantity but in a scattered and in a clumped distribution, (2) highly preferred fruit was scattered while the less preferred was clumped. Generally, primates preferred feeding first on the boxes of the clumped distribution in both conditions, with the more frugivorous species at a higher degree than the less frugivorous species in condition (1), but not (2). Therefore, what fruit was available changed the foraging decisions of the more frugivorous species who also engaged more in goal-directed travel. When feeding on preferred fruit, primates probably maximized foraging efficiency regardless of their degree of frugivory. Our findings emphasize that the food type and distribution may be a preponderant driver in cognitive evolution.

Do primates flexibly use spatio-temporal cues when foraging?

2020 ◽  
pp. 174702182097072
Author(s):  
Cinzia Trapanese ◽  
Hélène Meunier ◽  
Shelly Masi
Keyword(s):  
Brain Size ◽  
Seasonal Pattern ◽  
Temporal Distribution ◽  
Primate Species ◽  
Temporal Cues ◽  
Large Brain ◽  
Sapajus Apella ◽  
Average Proportion ◽  
Spatio Temporal ◽  
Free Ranging

Foraging in seasonal environments can be cognitively demanding. Comparative studies have associated large brain size with a frugivorous diet. We investigated the ability of three semi-free-ranging primate species with different degrees of frugivory ( Ntrials: Macaca tonkeana = 419, Macaca fascicularis = 197, Sapajus apella = 346) in developing a mental representation of the spatio-temporal distribution of food using foraging experiments. Forty-two boxes were fixed on trees, and each week (“season”), some of them were filled with fruits which were either highly preferred, or less preferred. Spatial (geometrical panels) and temporal (peel skin of the available fruit) cues were present at each season to indicate where (food location), what (which food) was available, and when. To test the flexible use of the cues in primate foraging behaviour, we first removed the spatial and temporal cues one at a time, and then, we manipulated the “seasonal” order of the available fruit. We compared the foraging performances in the absence and the presence of the cues and during the usual and unusual seasonal order. The average proportion of baited boxes chosen by the subjects in presence of both cues was high (between 73% and 98%) for all species. The primates seemed to remember the spatio-temporal food availability (or used other cues) because no difference was found between trials with or without our spatial and temporal cues. When the usual seasonal pattern was changed, they flexibly adjusted the feeding choice by using the provided temporal cues. We discuss these results also in view of a possible experimental bias.

scholarly journals A Farewell to the Encephalization Quotient: A New Brain Size Measure for Comparative Primate Cognition

2021 ◽  
pp. 1-12
Author(s):  
Carel P. van Schaik ◽  
Zegni Triki ◽  
Redouan Bshary ◽  
Sandra A. Heldstab
Keyword(s):  
Body Size ◽  
Cognitive Abilities ◽  
Brain Size ◽  
Estimation Error ◽  
Primate Species ◽  
Mammal Species ◽  
Mean Values ◽  
Encephalization Quotient ◽  
Body Sizes ◽  
Size Measure

Both absolute and relative brain sizes vary greatly among and within the major vertebrate lineages. Scientists have long debated how larger brains in primates and hominins translate into greater cognitive performance, and in particular how to control for the relationship between the noncognitive functions of the brain and body size. One solution to this problem is to establish the slope of cognitive equivalence, i.e., the line connecting organisms with an identical bauplan but different body sizes. The original approach to estimate this slope through intraspecific regressions was abandoned after it became clear that it generated slopes that were too low by an unknown margin due to estimation error. Here, we revisit this method. We control for the error problem by focusing on highly dimorphic primate species with large sample sizes and fitting a line through the mean values for adult females and males. We obtain the best estimate for the slope of circa 0.27, a value much lower than those constructed using all mammal species and close to the value expected based on the genetic correlation between brain size and body size. We also find that the estimate of cognitive brain size based on cognitive equivalence fits empirical cognitive studies better than the encephalization quotient, which should therefore be avoided in future studies on primates and presumably mammals and birds in general. The use of residuals from the line of cognitive equivalence may change conclusions concerning the cognitive abilities of extant and extinct primate species, including hominins.

scholarly journals Molecular evolutionary analysis of human primary microcephaly genes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nashaiman Pervaiz ◽  
Hongen Kang ◽  
Yiming Bao ◽  
Amir Ali Abbasi
Keyword(s):  
Evolutionary History ◽  
Genetic Basis ◽  
Brain Size ◽  
Primate Species ◽  
Evolutionary Analysis ◽  
Australopithecus Afarensis ◽  
Primary Microcephaly ◽  
Modern Humans ◽  
History Of ◽  
The Brain

Abstract Background There has been a rapid increase in the brain size relative to body size during mammalian evolutionary history. In particular, the enlarged and globular brain is the most distinctive anatomical feature of modern humans that set us apart from other extinct and extant primate species. Genetic basis of large brain size in modern humans has largely remained enigmatic. Genes associated with the pathological reduction of brain size (primary microcephaly-MCPH) have the characteristics and functions to be considered ideal candidates to unravel the genetic basis of evolutionary enlargement of human brain size. For instance, the brain size of microcephaly patients is similar to the brain size of Pan troglodyte and the very early hominids like the Sahelanthropus tchadensis and Australopithecus afarensis. Results The present study investigates the molecular evolutionary history of subset of autosomal recessive primary microcephaly (MCPH) genes; CEP135, ZNF335, PHC1, SASS6, CDK6, MFSD2A, CIT, and KIF14 across 48 mammalian species. Codon based substitutions site analysis indicated that ZNF335, SASS6, CIT, and KIF14 have experienced positive selection in eutherian evolutionary history. Estimation of divergent selection pressure revealed that almost all of the MCPH genes analyzed in the present study have maintained their functions throughout the history of placental mammals. Contrary to our expectations, human-specific adoptive evolution was not detected for any of the MCPH genes analyzed in the present study. Conclusion Based on these data it can be inferred that protein-coding sequence of MCPH genes might not be the sole determinant of increase in relative brain size during primate evolutionary history.

Modeling social styles in macaque societies applied to a semi-free-ranging group of Macaca tonkeana

2021 ◽  
Vol 75 (3) ◽  
Author(s):  
Ruth Dolado ◽  
Elisabet Gimeno ◽  
Hélène Meunier ◽  
Francesc S. Beltran
Keyword(s):  
Macaca Tonkeana ◽  
Free Ranging

scholarly journals The corpus callosum in primates: processing speed of axons and the evolution of hemispheric asymmetry

2015 ◽  
Vol 282 (1818) ◽  
pp. 20151535 ◽  
Author(s):  
Kimberley A. Phillips ◽  
Cheryl D. Stimpson ◽  
Jeroen B. Smaers ◽  
Mary Ann Raghanti ◽  
Bob Jacobs ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Conduction Velocity ◽  
Processing Speed ◽  
Hemispheric Asymmetry ◽  
Brain Size ◽  
Myelinated Axon ◽  
Primate Species ◽  
Limiting Factor ◽  
Interhemispheric Communication ◽  
Transmission Delays

Interhemispheric communication may be constrained as brain size increases because of transmission delays in action potentials over the length of axons. Although one might expect larger brains to have progressively thicker axons to compensate, spatial packing is a limiting factor. Axon size distributions within the primate corpus callosum (CC) may provide insights into how these demands affect conduction velocity. We used electron microscopy to explore phylogenetic variation in myelinated axon density and diameter of the CC from 14 different anthropoid primate species, including humans. The majority of axons were less than 1 µm in diameter across all species, indicating that conduction velocity for most interhemispheric communication is relatively constant regardless of brain size. The largest axons within the upper 95th percentile scaled with a progressively higher exponent than the median axons towards the posterior region of the CC. While brain mass among the primates in our analysis varied by 97-fold, estimates of the fastest cross-brain conduction times, as conveyed by axons at the 95th percentile, varied within a relatively narrow range between 3 and 9 ms across species, whereas cross-brain conduction times for the median axon diameters differed more substantially between 11 and 38 ms. Nonetheless, for both size classes of axons, an increase in diameter does not entirely compensate for the delay in interhemispheric transmission time that accompanies larger brain size. Such biophysical constraints on the processing speed of axons conveyed by the CC may play an important role in the evolution of hemispheric asymmetry.

scholarly journals The incursion of free-ranging dogs into protected areas: A spatio-temporal analysis in a network of giant panda reserves

2022 ◽  
Vol 265 ◽  
pp. 109423
Author(s):  
Yue Weng ◽  
William McShea ◽  
Yixin Diao ◽  
Hongbo Yang ◽  
Xiaofeng Zhang ◽  
...  
Keyword(s):  
Protected Areas ◽  
Giant Panda ◽  
Temporal Analysis ◽  
Spatio Temporal ◽  
Free Ranging

Brain size/body weight in the dingo (Canis dingo): comparisons with domestic and wild canids

2017 ◽  
Vol 65 (5) ◽  
pp. 292 ◽  
Author(s):  
Bradley P. Smith ◽  
Teghan A. Lucas ◽  
Rachel M. Norris ◽  
Maciej Henneberg
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Cuon Alpinus ◽  
Size Relationship ◽  
Wild Canids ◽  
Free Ranging ◽  
The Impact ◽  
Endocranial Volume ◽  
The Brain

Endocranial volume was measured in a large sample (n = 128) of free-ranging dingoes (Canis dingo) where body size was known. The brain/body size relationship in the dingoes was compared with populations of wild (Family Canidae) and domestic canids (Canis familiaris). Despite a great deal of variation among wild and domestic canids, the brain/body size of dingoes forms a tight cluster within the variation of domestic dogs. Like dogs, free-ranging dingoes have paedomorphic crania; however, dingoes have a larger brain and are more encephalised than most domestic breeds of dog. The dingo’s brain/body size relationship was similar to those of other mesopredators (medium-sized predators that typically prey on smaller animals), including the dhole (Cuon alpinus) and the coyote (Canis latrans). These findings have implications for the antiquity and classification of the dingo, as well as the impact of feralisation on brain size. At the same time, it highlights the difficulty in using brain/body size to distinguish wild and domestic canids.

scholarly journals Activity budget and behavioural patterns of free-ranging yellow-tailed woolly monkeys Oreonax flavicauda (Mammalia: Primates), at La Esperanza, northeastern Peru

2011 ◽  
Vol 80 (4) ◽  
pp. 269-277 ◽  
Author(s):  
Sam Shanee ◽  
Noga Shanee
Keyword(s):  
Secondary Forest ◽  
Primate Species ◽  
Forest Types ◽  
Woolly Monkey ◽  
Woolly Monkeys ◽  
Focal Animal ◽  
Behavioural Patterns ◽  
North Eastern ◽  
Free Ranging ◽  
The Village

The critically endangered yellow-tailed woolly monkey (Oreonax flavicauda) is endemic to the cloud forests of north-eastern Peru and one of the least studied of all primate species. We conducted fifteen months of group follows using focal animal sampling techniques to gather the first behavioural data on free ranging O. flavicauda. Group follows took place in an area of disturbed primary and regenerating secondary forest near the village of La Esperanza, Amazonas department. Yellow-tailed woolly monkey activity budgets at La Esperanza average: 29.8% feeding, 26.3% resting, 29.0% travelling, 2.3% in social and 12.8% in other activities. Significant differences were observed in the frequency of behaviours between age/sex classes as well as on temporal scales. Our findings are similar to those of other woolly monkey species although yellow-tailed woolly monkeys were found to be more vocally active then other species. We recommend further study of this species at other sites with different forest types to better understand its behavioural ecology and conservation needs. Particular emphasis should be given to studying this species at different altitudes.

scholarly journals Social foraging and individual consistency in following behaviour: testing the information centre hypothesis in free-ranging vultures

2017 ◽  
Vol 284 (1852) ◽  
pp. 20162654 ◽  
Author(s):  
Roi Harel ◽  
Orr Spiegel ◽  
Wayne M. Getz ◽  
Ran Nathan
Keyword(s):  
Spatial Scales ◽  
Social Foraging ◽  
Foraging Efficiency ◽  
Information Centre ◽  
Gyps Fulvus ◽  
Declining Populations ◽  
Tracking Movements ◽  
Communal Roosting ◽  
Individual Consistency ◽  
Free Ranging

Uncertainties regarding food location and quality are among the greatest challenges faced by foragers and communal roosting may facilitate success through social foraging. The information centre hypothesis (ICH) suggests that uninformed individuals at shared roosts benefit from following informed individuals to previously visited resources. We tested several key prerequisites of the ICH in a social obligate scavenger, the Eurasian griffon vulture ( Gyps fulvus ), by tracking movements and behaviour of sympatric individuals over extended periods and across relatively large spatial scales, thereby precluding alternative explanations such as local enhancement. In agreement with the ICH, we found that ‘informed’ individuals returning to previously visited carcasses were followed by ‘uninformed’ vultures that consequently got access to these resources. When a dyad (two individuals that depart from the same roost within 2 min of each other) included an informed individual, they spent a higher proportion of the flight time close to each other at a shorter distance between them than otherwise. Although all individuals occasionally profited from following others, they differed in their tendencies to be informed or uninformed. This study provides evidence for ‘following behaviour’ in natural conditions and demonstrates differential roles and information states among foragers within a population. Moreover, demonstrating the possible reliance of vultures on following behaviour emphasizes that individuals in declining populations may suffer from reduced foraging efficiency.

scholarly journals Relaxed genetic control of cortical organization in human brains compared with chimpanzees

2015 ◽  
Vol 112 (48) ◽  
pp. 14799-14804 ◽  
Author(s):  
Aida Gómez-Robles ◽  
William D. Hopkins ◽  
Steven J. Schapiro ◽  
Chet C. Sherwood
Keyword(s):  
Genetic Control ◽  
Cultural Context ◽  
Brain Size ◽  
Environmental Influence ◽  
Modern Human ◽  
Primate Species ◽  
Additional Line ◽  
Cortical Organization ◽  
Anatomical Basis ◽  
Human Brains

The study of hominin brain evolution has focused largely on the neocortical expansion and reorganization undergone by humans as inferred from the endocranial fossil record. Comparisons of modern human brains with those of chimpanzees provide an additional line of evidence to define key neural traits that have emerged in human evolution and that underlie our unique behavioral specializations. In an attempt to identify fundamental developmental differences, we have estimated the genetic bases of brain size and cortical organization in chimpanzees and humans by studying phenotypic similarities between individuals with known kinship relationships. We show that, although heritability for brain size and cortical organization is high in chimpanzees, cerebral cortical anatomy is substantially less genetically heritable than brain size in humans, indicating greater plasticity and increased environmental influence on neurodevelopment in our species. This relaxed genetic control on cortical organization is especially marked in association areas and likely is related to underlying microstructural changes in neural circuitry. A major result of increased plasticity is that the development of neural circuits that underlie behavior is shaped by the environmental, social, and cultural context more intensively in humans than in other primate species, thus providing an anatomical basis for behavioral and cognitive evolution.

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