Social system and independence of offspring in tree shrews

Field observations on 117 tree shrews (Tupaia glis) were conducted over a period of six months in Singapore. Of 19 groups (pairs or harems, with or without offspring), nine changed their composition mainly through the disappearance of juveniles. Juvenile males tended to disappear earlier than juvenile females. The areas used by the groups remained stable throughout their disappearance and membership changes. The onset of mating was observed in December, and the synchronous disappearance of offspring of the preceding reproduction typically occurred in late January. However, in one group, two litters coexisted. Offspring were usually excluded from their group presumably by the adult member of the same sex. Males disappeared at the timing of oestrus in their mothers, while females probably disappeared during the later stages of pregnancy of their mothers.