Some problems associated with using the index E (relative exclusivenes
s of use of space, Alho, 1979) to analyze the spatial structure in sma
ll mammal populations and different ways of its calculation are discus
sed. Calculating the index E, executed on the basis of dyads, is shown
to make possible a comparison between any sex-age groups of individua
ls using any sampling size. Concrete examples for populations of Mongo
lian gerbils (Meriones unguiculatus) have been adduced.