PhD Thesis by Patrik Lindenfors

Sexual size dimorphism is when the two sexes (males and females) are of unequal sizes. A familiar example of this is humans where males on average are larger (taller and heavier) than females.

The main question addressed in this PhD thesis is why such size differences between the sexes has evolved. The approach to answering this question was phylogenetic, meaning that phylogenies (trees showing the relatedness between species) are used for the analysis.

Mainly primates were studied, but also pinnipeds and shorebirds. These groups were chosen because they contain a lot of variation in size dimorphism.

The thesis was carried out by myself, Patrik Lindenfors (, and supervised by professor Birgitta Tullberg ( It was publically defended 2002-02-22 with Professor John Gittleman as opponent. If you want a copy of the thesis, just send an e-mail.