In some primate species, pregnancy and infant care results in an increase in nutritional demands on the mother and other caregivers, which is complicated by seasonal changes in food abundance and availability. This study examines whether changes in feeding strategies or the microbiome facilitate the maintenance of a healthy nutritional status in mothers and caregivers in a non-human primate species (tamarins). The study collects data on mothers and helpers throughout the course of pregnancy and the subsequent period of infant care. Behavioral data is collected, and biotechnological methods are applied in the analyses of food nutrient content and the composition of individual microbiomes. The study advances knowledge and generates comparative data for understanding reproductive fitness and provides training and research opportunities to students and develops engaging outreach activities. To assess how mothers and alloparents maintain their nutritional status, this study collects data on food, nutrient content, behavior and microbiome in a non-human primate cooperative breeding species. Daily follows are conducted in subadults and adults, so that two days of observational data per adult/subadult is generated. Behavioral data is complemented with focal and continuous sampling. During behavioral observations, all food consumption is registered. Weekly fecal samples are collected for each individual, and they are examined with biotechnology methods to calculate food digestibi