Reproductive Patterns and Birth Seasonality in a South-American Breeding Colony of Common Marmosets, Callithrix jacchus

Abstract

We analyzed data on captive-born and wild-caught females housed under natural conditions in a colony located in northeastern Brazil. No differences in reproductive performance were found between captive-born and wild-caught females. Twins were the most frequent litter size, followed by triplets and singletons. No parity effect was observed, with similar infant survival for nulliparous and multiparous females. No significant departures in sex ratio were detected for births and mortality of the male and female infants. The age of the females at the time of pairing showed a negative correlation with pairing-parturition length, but did not affect infant survival. The prolongation in pairing-parturition interval (PPI) and interbirth interval (IBI) was related to birth seasonality. The births were clustered in the second half of the dry season and the beginning of the wet season (November-March), and the time of pairing and the time of infant birth influenced the PPI and IBI, respectively. The use of outdoor cages, which allowed the animals to be aware of the seasonal variations in photo-period and rainfall seems to be sufficient to time the reproductive activity, even when the animals are maintained on a constant food supply.