Common treeshrews practise an absentee maternal system. The female builds a second nest for her litter, away from her own, and returns at intervals of about two days. A visit lasts only a few minutes, during which the young take a large volume of milk. Between visits they are alone and unattended, and the mother identifies them by a scent she marks them with.
The system works because of milk composition. Treeshrew milk is very high in fat and protein compared with most mammals, so a short bout delivers enough energy for two days. The young grow quickly and leave the nest between about twenty-five and thirty-five days of age. Field and captive observations agree on the basic pattern.
Treeshrews are also frequently miscast in evolutionary narratives as primitive primates or as a model of the primate ancestor. They are neither: they form their own order, Scandentia, related to primates and colugos but not ancestral to them. They are also not shrews. The exact branching order among treeshrews, colugos and primates has been rearranged more than once and is still argued over.