Litter size and infant survivorship in wild groups of cotton‐top tamarins (Saguinus oedipus) in Colombia

Abstract

Cotton-top tamains (Saguinus oedipus) are a critically endangered primate found only in Colombia. Efforts to conserve this species are centered on developing effective management plans that integrate biological information regarding population dynamics and factors that influence their survival. This study documented infants born to wild cotton-top tamarin females from 1994-2008 at two distinct field sites in northern Colombia. Our studies have shown that wild cotton-top tamarins typically give birth to one litter each year and infant survival to 6 months of age was greater in the wild than has been reported in captive colonies. However, similar to reports from captive colonies, litter size of wild cotton-top tamarins ranges from 1-3 infants, with twin litters most common. Here we report the first occurrence of triplet litters in nearly 20 years of observing wild cotton-top tamarin groups. Over the first 3 months of life, wild-born infants exhibited highest mortality during the first week of life, similar to reports from captive colonies. Infant survival in the wild also increases with successive litters as it does in captivity. However, inter-birth interval, group size, and the number of adult males in the group did not appear to influence infant survival in the wild. The value of such long-term data from field studies aids in the information that can be used to model future population trends and develop effective conservation plans for this critically endangered primate.

Developmental Origins of Pregnancy Loss in the Adult Female Common Marmoset Monkey (Callithrix jacchus)

“…Individual repeatability of litter size is low, and the litter size a female experiences as a fetus does not predict the litter size she will produce as an adult, together suggesting that litter size is not genetically constrained but ecologically responsive [16], [20], [21]. Importantly, several occurrences of triplets have been observed in wild callitrichine species as well (cotton-top tamarins [22]; common marmosets [23]; golden lion tamarins [24]). This suggests that conceiving and gestating (although not rearing [19], [25]) more than two fetuses may be a common a feature of callitrichine reproductive biology both in the wild and in captivity.…”

An Assessment of the Population of Cotton-Top Tamarins (Saguinus oedipus) and Their Habitat in Colombia

“…With our current dataset, it is difficult to determine what population dynamics contributed to the relatively stable population size from 2005 to 2012. Although we cannot determine if some of these surveyed populations are potential ecological sinks, additional data from other studies on this species suggest that stability is an accurate representation of the cotton-top tamarin population for the sampled areas [27, 28]. Reproductive rates of cotton-top tamarins from a long-term research project at Hacienda Ceibal (Bolivar), one of the surveyed patches, have remained stable: on average each adult female produces two offspring a year [27] and infant mortality rates are low [28].…”

“…Since 1987, Proyecto Tití has been leading the effort to bring increased national and international attention to the conservation efforts of cotton-top tamarins in Colombia [29] through scientific investigation [9, 28, 30], community empowerment and sustainable development [31, 32], education [8], training of Colombian nationals, and protection of habitat in the department of Atlántico and Bolívar [8]. Proyecto Tití directly lead in the protection and conservation of habitat by working to establish two protected areas: El Parque Natural Regional Bosque Seco El Ceibal Mono Tití (Cotton-top Tamarin Regional Park in Bolívar) [33] and Parque Natural Regional Los Rosales in Atlántico [34], which added legal protection to 1,724 hectares of forest.…”

Mother's little helpers: What we know (and don't know) about cooperative infant care in callitrichines

“…This is known as the "group augmentation" hypothesis. Among cooperative breeders, the presence of helpers (i.e., larger groups) is positively correlated with increased breeding success and survival (Clutton-Brock, 2002 Among callitrichines, infant survival is correlated with group size ( Figure 2), with particular importance attributed to the number of adult males (Koenig, 1995;Garber, 1998;Bales et al, 2000; but see Savage, Soto, Medina, Emeris, & Soltis, 2009), suggesting that in this taxon there are fitness benefits associated with larger groups. Although there has been no explicit test, there is some anecdotal support for this hypothesis in callitrichines.…”

“…Among callitrichines, infant survival is correlated with group size (Figure 2), with particular importance attributed to the number of adult males (Koenig, ; Garber, ; Bales et al, ; but see Savage, Soto, Medina, Emeris, & Soltis, ), suggesting that in this taxon there are fitness benefits associated with larger groups. Although there has been no explicit test, there is some anecdotal support for this hypothesis in callitrichines.…”