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Suire A, Kunita I, Harel R, Crofoot M, Mutinda M, Kamau M, Hassel JM, Murray S, Kawamura S, Matsumoto-Oda A. Estimating individual exposure to predation risk in group-living baboons, Papio anubis. PLoS One 2023; 18:e0287357. [PMID: 37939092 PMCID: PMC10631679 DOI: 10.1371/journal.pone.0287357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 10/16/2023] [Indexed: 11/10/2023] Open
Abstract
In environments with multiple predators, vulnerabilities associated with the spatial positions of group-living prey are non-uniform and depend on the hunting styles of the predators. Theoretically, coursing predators follow their prey over long distances and attack open areas, exposing individuals at the edge of the group to predation risk more than those at the center (marginal predation). In contrast, ambush predators lurk unnoticed by their prey and appear randomly anywhere in the group; therefore, isolated individuals in the group would be more vulnerable to predators. These positions of vulnerability to predation are expected to be taken by larger-bodied males. Moreover, dominant males presumably occupy the center of the safe group. However, identifying individuals at higher predation risk requires both simultaneous recording of predator location and direct observation of predation events; empirical observations leave ambiguity as to who is at risk. Instead, several theoretical methods (predation risk proxies) have been proposed to assess predation risk: (1) the size of the individual 'unlimited domain of danger' based on Voronoi tessellation, (2) the size of the 'limited domain of danger' based on predator detection distance, (3) peripheral/center position in the group (minimum convex polygon), (4) the number and direction of others in the vicinity (surroundedness), and (5) dyadic distances. We explored the age-sex distribution of individuals in at-risk positions within a wild baboon group facing predation risk from leopards, lions, and hyenas, using Global Positioning System collars. Our analysis of the location data from 26 baboons revealed that adult males were consistently isolated at the edge of the group in all predation risk proxies. Empirical evidence from previous studies indicates that adult male baboons are the most frequently preyed upon, and our results highlights the importance of spatial positioning in this.
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Affiliation(s)
- Alexandre Suire
- Faculty of Global and Regional Studies, University of the Ryukyus, Okinawa, Japan
| | - Itsuki Kunita
- Faculty of Engineering, University of the Ryukyus, Okinawa, Japan
| | - Roi Harel
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, Konstanz, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Margaret Crofoot
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, Konstanz, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Maureen Kamau
- Smithsonian Conservation Biology Institute, Global Health Program, Washington, DC, United States of America
- Mpala Research Centre, Nanyuki, Kenya
| | - James M. Hassel
- Smithsonian Conservation Biology Institute, Global Health Program, Washington, DC, United States of America
| | - Suzan Murray
- Smithsonian Conservation Biology Institute, Global Health Program, Washington, DC, United States of America
| | - Shoji Kawamura
- Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Akiko Matsumoto-Oda
- Graduate School of Tourism Sciences, University of the Ryukyus, Okinawa, Japan
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Sarıca M, Karakoç K, Erensoy K. Effects of varying group sizes on performance, body defects, and productivity in broiler chickens. Arch Anim Breed 2022; 65:171-181. [PMID: 35572012 PMCID: PMC9097258 DOI: 10.5194/aab-65-171-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 04/12/2022] [Indexed: 11/24/2022] Open
Abstract
This study aimed to determine the changes in the performance, welfare, and productivity level of broiler chickens reared at various group sizes
(GS3000, GS4000, GS6000, and GS20 000) under intensive field conditions. The study was carried out according to a randomized block design with
four different group sizes (GS) in three trials. Weekly body weights (BWs) were determined randomly in 150 individuals from each GS group. Feed intake (FI),
feed conversion ratio (FCR), and European production efficiency factor (EPEF) were determined for each GS treatment. Body defects (footpad
dermatitis, FPD, hock burn, HB, and the breast burn, BB) were measured randomly in 150 chickens
(75 male and 75 female) from each group using a visual scoring system with a 0–3 scale. At 1 and 2 weeks of age, GS3000 broilers had similar BW
to GS6000 and higher than GS4000 and GS20 000. However, this situation changed at 6 weeks of age and the male chickens in GS6000 became heavier
than in GS3000, GS4000 and GS20 000 (P = 0.007). No differences in mean values of temperature, humidity, air velocity and litter moisture
levels were observed among GS treatments. GS3000 and GS4000 chickens had significantly lower levels of FPD, HB, and BB than chickens reared in
GS6000 and GS20 000 (P < 0.001). The EPEF values from highest to lowest were 425.8, 404.5, 358.8, and 354.0 in the GS6000 GS3000, GS4000, and
GS20 000 groups, respectively. In conclusion, our study results showed that rearing in groups of 6000 broilers had both better performance and higher
overall productivity than other groups but tended to show more severe body defects.
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Farine DR, Strandburg-Peshkin A, Couzin ID, Berger-Wolf TY, Crofoot MC. Individual variation in local interaction rules can explain emergent patterns of spatial organization in wild baboons. Proc Biol Sci 2017; 284:20162243. [PMID: 28424342 PMCID: PMC5413915 DOI: 10.1098/rspb.2016.2243] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 03/20/2017] [Indexed: 11/21/2022] Open
Abstract
Researchers have long noted that individuals occupy consistent spatial positions within animal groups. However, an individual's position depends not only on its own behaviour, but also on the behaviour of others. Theoretical models of collective motion suggest that global patterns of spatial assortment can arise from individual variation in local interaction rules. However, this prediction remains untested. Using high-resolution GPS tracking of members of a wild baboon troop, we identify consistent inter-individual differences in within-group spatial positioning. We then apply an algorithm that identifies what number of conspecific group members best predicts the future location of each individual (we call this the individual's neighbourhood size) while the troop is moving. We find clear variation in the most predictive neighbourhood size, and this variation relates to individuals' propensity to be found near the centre of their group. Using simulations, we show that having different neighbourhood sizes is a simple candidate mechanism capable of linking variation in local individual interaction rules-in this case how many conspecifics an individual interacts with-to global patterns of spatial organization, consistent with the patterns we observe in wild primates and a range of other organisms.
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Affiliation(s)
- D R Farine
- Department of Anthropology, University of California, 1 Shields Avenue, Davis, CA, USA
- Smithsonian Tropical Research Institute, Ancon, Panama
- Edward Grey Institute of Field Ornithology, Department of Zoology, University of Oxford, South Parks Road, Oxford, UK
| | - A Strandburg-Peshkin
- Department of Ecology and Evolutionary Biology, Princeton University, 106A Guyot Hall, Princeton, NJ, USA
| | - I D Couzin
- Department of Collective Behaviour, Max Planck Institute for Ornithology, 78464 Konstanz, Germany
- Chair of Biodiversity and Collective Behaviour, Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - T Y Berger-Wolf
- Department of Computer Science, University of Illinois at Chicago, 851 South Morgan Street, Chicago, IL, USA
| | - M C Crofoot
- Department of Anthropology, University of California, 1 Shields Avenue, Davis, CA, USA
- Animal Behavior Graduate Group, University of California, 1 Shields Avenue, Davis, CA, USA
- Smithsonian Tropical Research Institute, Ancon, Panama
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Assessing attraction or avoidance between rabbits: comparison of distance-based methods to analyse spatial distribution. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2011.08.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Evers E, de Vries H, Spruijt BM, Sterck EHM. Better safe than sorry--socio-spatial group structure emerges from individual variation in fleeing, avoidance or velocity in an agent-based model. PLoS One 2011; 6:e26189. [PMID: 22125595 PMCID: PMC3220670 DOI: 10.1371/journal.pone.0026189] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 09/22/2011] [Indexed: 11/19/2022] Open
Abstract
In group-living animals, such as primates, the average spatial group structure often reflects the dominance hierarchy, with central dominants and peripheral subordinates. This central-peripheral group structure can arise by self-organization as a result of subordinates fleeing from dominants after losing a fight. However, in real primates, subordinates often avoid interactions with potentially aggressive group members, thereby preventing aggression and subsequent fleeing. Using agent-based modeling, we investigated which spatial and encounter structures emerge when subordinates also avoid known potential aggressors at a distance as compared with the model which only included fleeing after losing a fight (fleeing model). A central-peripheral group structure emerged in most conditions. When avoidance was employed at small or intermediate distances, centrality of dominants emerged similar to the fleeing model, but in a more pronounced way. This result was also found when fleeing after a fight was made independent of dominance rank, i.e. occurred randomly. Employing avoidance at larger distances yielded more spread out groups. This provides a possible explanation of larger group spread in more aggressive species. With avoidance at very large distances, spatially and socially distinct subgroups emerged. We also investigated how encounters were distributed amongst group members. In the fleeing model all individuals encountered all group members equally often, whereas in the avoidance model encounters occurred mostly among similar-ranking individuals. Finally, we also identified a very general and simple mechanism causing a central-peripheral group structure: when individuals merely differed in velocity, faster individuals automatically ended up at the periphery. In summary, a central-peripheral group pattern can easily emerge from individual variation in different movement properties in general, such as fleeing, avoidance or velocity. Moreover, avoidance behavior also affects the encounter structure and can lead to subgroup formation.
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Affiliation(s)
- Ellen Evers
- Behavioural Biology, Utrecht University, Utrecht, The Netherlands.
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Separating the impact of group size, density, and enclosure size on broiler movement and space use at a decreasing perimeter to area ratio. Behav Processes 2009; 83:16-22. [PMID: 19733638 DOI: 10.1016/j.beproc.2009.08.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 08/29/2009] [Accepted: 08/29/2009] [Indexed: 11/20/2022]
Abstract
The goal of this study was to determine the impact of enclosure size on space use and movement patterns of domestic fowl (Gallus gallus domesticus), independent of group size and density. Research designed to estimate the effects of group size, density, or enclosure size involves inherent confounding between factors, clouding their individual effects. This experimental design enabled us to conduct multiple contrasts in order to tease apart the specific impacts. Treatments consisted of five combinations of three square enclosures: small (S; 1.5m(2)), medium (M; 3.0m(2)), and large (L; 4.5m(2)), and three group sizes of 10, 20, and 30 birds. We made comparisons while holding group size constant, holding density constant, and the third while maintaining a constant enclosure size. Nearest neighbor distances increased with enclosure size but appeared to be constrained by density. Net displacement and minimum convex polygons increased with enclosure size regardless of group size or density. We found no evidence of social restriction on space use. Results indicate that broilers adapted their use of space and movement patterns to the size of the enclosures, spreading out and utilizing a greater amount of space when it was available.
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Northcott J, Andersen MC, Roemer GW, Fredrickson EL, DeMers M, Truett J, Ford PL. Spatial Analysis of Effects of Mowing and Burning on Colony Expansion in Reintroduced Black-Tailed Prairie Dog (Cynomys ludovicianus). Restor Ecol 2008. [DOI: 10.1111/j.1526-100x.2007.00323.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Skarin A, Danell Ö, Bergström R, Moen J. Summer habitat preferences of GPS-collared reindeer Rangifer tarandus tarandus. WILDLIFE BIOLOGY 2008. [DOI: 10.2981/0909-6396(2008)14[1:shpogr]2.0.co;2] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Hewitson L, Gordon IJ, Dumont B. Social context affects patch-leaving decisions of sheep in a variable environment. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2006.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Romey WL, Wallace AC. Sex and the selfish herd: sexual segregation within nonmating whirligig groups. Behav Ecol 2007. [DOI: 10.1093/beheco/arm057] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Öst M, Jaatinen K, Steele B. Aggressive females seize central positions and show increased vigilance in brood-rearing coalitions of eiders. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2006.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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