Proyecto Tití, Inc, Orlando, Florida, USA.
Department of Psychology, University of Wisconsin, Madison, Wisconsin, USA.
Am J Primatol. 2021 Jul;83(7):e23262. doi: 10.1002/ajp.23262. Epub 2021 Apr 26.
Studies of cooperative breeding species have suggested that helpers are needed for infant survival and that helpers gain skills to successfully raise their own offspring. Studies of callitrichids in managed care and early field studies suggested that group size correlated with infant survival and that helpers needed to learn parental skills to be successful breeders. We present infant survival data from a 20-year field study of cotton-top tamarins (Saguinus oedipus) in Colombia involving 126 litters born to 41 females. There was no difference in the survival of male and female offspring to 6 months of age. However, litter size impacted survival, with triplet litters having lower survival and male triplets having lower survival than females. Loss of infants was highest in the first week of life and, of the animals remaining in the group at 6 months of age, 90% of them survived to 1 year. The mean length of time in the natal group was 2.3 years but some young migrated to other groups after 4 months of age. Group size and number of male helpers (>1 year) was not related to infant survival. However, groups with only one male had fewer surviving infants. Primiparous females had lower infant survival, but previous infant care experience by mothers as helpers had no effect on survival. A major cause of infant loss was group disruption due to deaths/evictions/loss of the reproductively active animals, or immigration of pregnant females. Thus, factors that cause a change in the stability of the reproductively active animals can disrupt group cohesion. Capture of individuals for the illegal pet trade, as well as habitat fragmentation, may increase competition between groups for access to territories and breeding opportunities. This may have long-term impacts to infant survival in this critically endangered species.
合作繁殖物种的研究表明，幼崽的生存需要帮手，而帮手则需要获得技能才能成功养育自己的后代。在受管理的护理和早期野外研究中对卷尾猴的研究表明，群体大小与幼崽的存活率相关，而且帮手需要学习亲代技能才能成为成功的繁殖者。我们提出了哥伦比亚一项为期 20 年的棉顶狨猴（Saguinus oedipus）野外研究的幼崽存活率数据，涉及 41 只雌性产下的 126 窝幼崽。雄性和雌性幼崽在 6 个月大时的存活率没有差异。然而，窝仔数对存活率有影响，三胞胎的存活率较低，雄性三胞胎的存活率低于雌性。在生命的第一周，幼崽的死亡率最高，在 6 个月大时留在群体中的动物中，有 90%的动物存活到 1 岁。幼崽在出生地群体中的平均时间为 2.3 年，但有些幼崽在 4 个月后迁移到其他群体。群体大小和雄性帮手数量（超过 1 年）与幼崽存活率无关。然而，只有一个雄性的群体中幸存的幼崽较少。初产雌性的幼崽存活率较低，但母亲作为帮手的先前育儿经验对存活率没有影响。幼崽死亡的主要原因是由于繁殖活跃动物的死亡/驱逐/丧失或怀孕雌性的移民，导致群体的瓦解。因此，导致繁殖活跃动物稳定性变化的因素可能会破坏群体凝聚力。个体被捕获用于非法宠物贸易，以及栖息地破碎化，可能会增加群体之间争夺领土和繁殖机会的竞争。这可能对这个极度濒危物种的幼崽存活率产生长期影响。
