How unpredictable is the individual scanning process in socially foraging mammals?

Pays, O, Blomberg, SP, Renaud, PC, Favreau, FR and Jarman, PJ (2010) How unpredictable is the individual scanning process in socially foraging mammals?. Behavioral Ecology And Sociobiology, 64 3: 443-454. doi:10.1007/s00265-009-0860-0


Author Pays, O
Blomberg, SP
Renaud, PC
Favreau, FR
Jarman, PJ
Title How unpredictable is the individual scanning process in socially foraging mammals?
Journal name Behavioral Ecology And Sociobiology   Check publisher's open access policy
ISSN 0340-5443
Publication date 2010-01-01
Year available 2009
Sub-type Article (original research)
DOI 10.1007/s00265-009-0860-0
Open Access Status Not yet assessed
Volume 64
Issue 3
Start page 443
End page 454
Total pages 12
Place of publication Germany
Publisher Springer
Language eng
Subject C1
970106 Expanding Knowledge in the Biological Sciences
060201 Behavioural Ecology
Abstract In group-forming prey species, theory assumes that individuals within groups should scan independently of one another, with vigilance sequences being relatively unpredictable, making interscan durations highly variable. We attempted to detect any divergence from randomness in the scanning process in three mammalian prey species phylogenetically and geographically separated and exposed to different levels of predation: waterbuck, Kobus ellipsiprymnus defassa, under a high observed predation risk, eastern grey kangaroo, Macropus giganteus, still experiencing occasional predation and European roe deer, Capreolus capreolus, under a very low natural predation risk. Our results revealed that the focal interscan duration increased when the duration of the preceding interscan increased, whatever the studied species and the predation risk that its individuals experienced, and decreased with the preceding scan duration in two species under, respectively, occasional and low predation risks. The exponential distribution was the tested model that fitted the observed distributions of interscan durations least well. We discuss what can trigger non-randomness in scanning, through a non-homogenous Poisson process, at both intra-individual and inter-individual levels, particularly with regard to previous studies that have demonstrated synchronisation of vigilance in such mammals. Our results suggest the need to reconsider any assumption of randomness in scanning in the basic model predicting form and frequency of scanning behaviour by prey species.
Formatted abstract
In group-forming prey species, theory assumes that individuals within groups should scan independently of one another, with vigilance sequences being relatively unpredictable, making interscan durations highly variable. We attempted to detect any divergence from randomness in the scanning process in three mammalian prey species phylogenetically and geographically separated and exposed to different levels of predation: waterbuck, Kobus ellipsiprymnus defassa, under a high observed predation risk, eastern grey kangaroo, Macropus giganteus, still experiencing occasional predation and European roe deer, Capreolus capreolus, under a very low natural predation risk. Our results revealed that the focal interscan duration increased when the duration of the preceding interscan increased, whatever the studied species and the predation risk that its individuals experienced, and decreased with the preceding scan duration in two species under, respectively, occasional and low predation risks. The exponential distribution was the tested model that fitted the observed distributions of interscan durations least well. We discuss what can trigger non-randomness in scanning, through a non-homogenous Poisson process, at both intra-individual and inter-individual levels, particularly with regard to previous studies that have demonstrated synchronisation of vigilance in such mammals. Our results suggest the need to reconsider any assumption of randomness in scanning in the basic model predicting form and frequency of scanning behaviour by prey species.
Keyword Vigilance
Anti-predator behaviour
Poisson process
Exponential distribution
Gamma distribution
Group living
Large mammalian herbivores
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Biological Sciences Publications
Ecology Centre Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 13 times in Thomson Reuters Web of Science Article | Citations
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Created: Sun, 28 Feb 2010, 10:06:20 EST