Two gerbils of the Negev: A long-term investigation of optimal habitat selection and its consequences

Michael L. Rosenzweig, Zvika Abramsky

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


Optimal foraging theory has entered a new phase. It is not so much tested as used. It helps behavioural ecologists discover the nature of the information in an animal's brain. It helps population ecologists reveal coefficients of interaction and their patterns of density-dependent variation. And it helps community ecologists examine niche relationships. In our studies on two species of Negev desert gerbil, we have taken advantage of the second and third of these functions. Both these gerbils prefer semi-stabilized dune habitat, and both altered their selective use of this habitat and stabilized sand according to experimental changes we made in their populations. Their changes in selectivity agree with a type of optimal foraging theory called 'isoleg theory'. Isoleg theories provide examples of dipswitch theories - bundles of articulated qualitative predictions - that are easier to falsify than single qualitative predictions. By linking behaviour to population dynamics through isoleg theory, we were able to use the behaviour of the gerbils to reveal the shapes of their competitive isoclines. These have the peculiar non-linear shapes predicted by optimal foraging theory. Finally, when owl predation threatens, the behaviour of Gerbillus allenbyi reveals the shape of their victim isocline. As has long been predicted by predation theory and laboratory experiments, it is unimodal.

Original languageEnglish (US)
Pages (from-to)733-756
Number of pages24
JournalEvolutionary Ecology
Issue number6
StatePublished - 1997
Externally publishedYes


  • Community ecology
  • Competition
  • Density dependence
  • Dipswitch theory
  • Gerbil
  • Habitat selection
  • Ideal free distribution
  • Interaction coefficient
  • Isocline
  • Isoleg
  • Mutualism
  • Optimal foraging
  • Population dynamics
  • Predation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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