Sociality of ground squirrels: effect of body size ad habitat type [Socialité des écureuils terrestres: effet de la taille du corps et du type d'habitat].

Résumé

I studied variation in sociality of 16 species of North American and Eurasian ground squirrels in relation to body size and degree of habitat openness using literature and original data. I hypothesized that degree of sociality would increase with body size and habitat openness due to combined effect of two factors that extends lateral view. Principle component analysis and multidimensional scaling were used to extract factor of sociality from 14 unitial variables that described territorial relationships, dispersal and breeding patterns, malefemale associations and nepotism. As predicted sociality appeared to increase with increase in body size and habitat openness. Moreover, species inhabiting "open" areas were more social whereas species of "closed" habitats tended to be less social than it was predicted from body size. Thus, single effect of extended lateral view rather than body size and habitat openness as separate factors is considered to stimulate development of sociality in ground squirrels.