Development of behaviour in the pouched mouse Saccostomus Campestris

Abstract

Saccostomus campestris is a seasonal breeder and this affects the age at which the female produces her first litter. Increasing the photoperiod and temperature induces fertility in both sexes. Litter size ranged from 2 to 8, with an average of 4,9. The minimum age at sexual maturity was 46 days and the shortest interval between litters 24 days; the gestation period is 21 days. S. campestris is born with a dense hair covering but is not precoci.al. No nipple clinging is present; suckling continued sporadically for 8 weeks, although weaning started at 3 weeks. There are four natural periods which reflect the critical development of the young. In the neonatal period the tactile response is most strongly developed; huddling is important for protection and warmth. This period is critical for survival as young are totally dependent on the mother. The transitional period is characterised by a significant increase in motor capabilities, allowing for greater contact between littermates and parents, and thus formation of the first social bonds. During the socialisation period the young become increasingly independent as sight develops; social interactions are increased. The most important factor during the juvenile period is the development of sexual behaviour and aggression. S. campestris is primarily nocturnal, but is also active during the day. It is an efficient digger and lives in burrows. Hoarding, which is independent of hunger, is strongly developed, and large quantities of hard foods are stored within the nest area; for this purpose, it uses the well-developed cheek pouches. S. campestris explores and forages extensively. Nest building is independent of sex, construction depending on the ambient temperature and number of individuals utilising the nest. Sandbathing, which is also common to both sexes, has both grooming and marking functions. Breeding was inhibited by female intolerance, which was further aggravated by the restricted space. Conflict was slightly reduced by keeping littermates in pairs. Threat was minimal, and aggression characterised by 'roll ball t fighting. Amicable behaviour between conspecifics was infrequent. The factors indicating the asocial and solitary nature of S. carnpestris are discussed