Cookies Policy
X
Cookie Policy

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.

I accept this policy

Find out more here

Mortality Risk of Spatial Positions in Animal Groups: the Danger of Being in the Front

MyBook is a cheap paperback edition of the original book and will be sold at uniform, low price.

Buy this article

Price:
$30.00+ Tax (if applicable)
Add to Favorites

image of Behaviour

We modified Hamilton's (1971) selfish herd model by introducing directional movement to the prey groups and the predators. The consequences of this modification with regards to differential predation risks are compared to Hamilton's original model (using stationary prey groups) and tested against empirical data. In model 1, we replicated Hamilton's original predator-prey system. In models 2 and 3, prey groups were mobile and predators were mobile (model 2) or stationary (model 3). Our results indicate that additional to the positive risk gradient from centre to periphery predicted by Hamilton's model for stationary groups, there might be another positive risk gradient from the rear to the front part in moving groups. Furthermore, models 2 and 3 suggest that moving groups should generally exhibit an elongated shape (longer than wide along the axis of locomotion) if risk minimisation is the only factor concerned. Also smaller inter-individual distances are predicted for front individuals than individuals elsewhere in the group. Empirical data based on the three-dimensional structure of fish shoals (using roach, Rutilus rutilus) were consistent with the above two predictions. A second experiment which involved lake chub, Semotilus atromaculatus, as prey and rock bass, Ambloplites rupestris, as predators, provided direct support for the hypothesis that individuals in front positions of groups incurred a significantly higher predation risk than fish in rear positions. Finally, we discuss the differential risks of different group positions in the context of potential foraging gains which provides the basis for a dynamic model of position preferences in group-living animals.

Affiliations: 1: Marine Biology Laboratories, 7 MBL Street, Woods Hole, MA 02543, Institut für Verhaltensbiologie, Freie Universität Berlin, Haderslebenstrasse 9, 12163 Berlin, Germany; 2: Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544-1003, USA, Department of Biology, University of Leeds, Leeds LS2 9JT, UK; 3: Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544-1003, USA

Sign-in

Can't access your account?
  • Tools

  • Add to Favorites
  • Printable version
  • Email this page
  • Create email alert
  • Get permissions
  • Recommend to your library

    You must fill out fields marked with: *

    Librarian details
    Name:*
    Email:*
    Your details
    Name:*
    Email:*
    Department:*
    Why are you recommending this title?
    Select reason:
     
     
     
     
    Other:
     
    Behaviour — Recommend this title to your library

    Thank you

    Your recommendation has been sent to your librarian.

  • Export citations
  • Key

  • Full access
  • Open Access
  • Partial/No accessInformation