The yellow-necked mouse is nocturnal. It is active on the ground and in the tree canopy and has a home range rather smaller than half a hectare. Besides nuts, it feeds on buds, shoots, fruit, seedling plants and sometimes small invertebrates. Breeding takes place at any time between February and October with successive pregnancies occurring at short intervals. The gestation period is about twenty six days and females can remate while still feeding the previous litter. A litter of young is born in a nesting chamber lined with dry plant material and consists of two to eleven (usually five) altricial young born naked, blind and helpless. The eyes of the young open after about a fortnight and their yellow collars are visible by then as grey patches. They are weaned at about eighteen days old. If they are born early in the year, they may start breeding in the same year, but late-born young become sexually mature in the following spring.