Evolution of group size in the superfamily Delphinoidea (Delphinidae, Phocoenidae and Monodontidae): a quantitative comparative analysis

Author: Gygax, Lorenz

Source: Mammal Review, Volume 32, Number 4, December 2002 , pp. 295-314(20)

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Abstract:

Predictors of group size in Delphinoidea were investigated in a comparative study. Possible predictors included phylogenetic variables, variables of the physical environment, the diet, correlates of predation pressure and life-history parameters. The strongest predictors were the variables species and subfamily, which explained most of the observed variation in group size. Group size also increased with openness of the habitat and showed a U-shaped relationship with temperature. In conclusion, phylogeny seems to play the most crucial role in the evolution of group size in Delphinoidea. The simplest interpretation of this result is that group size resulted from a historical (random) process and has only been marginally shaped by direct selection.

Document Type: Research article

DOI: http://dx.doi.org/10.1046/j.1365-2907.2002.00114.x

Affiliations: 1: Applied Mathematics, University of Zürich-Irchel, Zürich, Switzerland

Publication date: 2002-12-01