Should I store, or should I sync? The breeding strategy of two small Neotropical primates under predictable resource availability.

Primates employ many strategies to deal with the costs of reproduction. While income breeders exploit the food available in their environment during lactation, the most costly phase of reproduction, capital breeders tend to store energy for use in the period. We analyzed the relationship between resource availability and lactation in Callicebus coimbrai (n = 2 groups) and Callicebus nigrifrons (n = 2 groups) in four Brazilian Atlantic forest remnants, to assess their breeding strategy. We recorded the occurrence of births and breastfeeding events to assess birth seasonality and lactation period and length while monitoring monthly fruit availability. We recorded 11 births (five for C. coimbrai, and six for C. nigrifrons), all restricted to the end of the lean season and the beginning of the rich season. Lactation coincided with periods of increased fruit availability. We suggest that the breeding pattern of Callicebus coimbrai and C. nigrifrons is compatible with an income-based breeding strategy.

Births during 7 years after the translocation of a pair of black-and-gold howler monkeys (Alouatta caraya) to a forest fragment in southeast Brazil.

Fecundity in female primates is influenced by the nutritional condition. If when translocated howler monkeys exhibit the same breeding patterns as non-translocated members of the same genus, it is an indication that the translocated monkeys have become well adapted to their release site and that they are likely in good nutritional condition. The objective of this study was therefore to investigate this pattern by recording copulations (over 5 years) and births (over 7 years) after the translocation of a pair of black-and-gold howler monkeys (Alouatta caraya) and to evaluate their gestation period, seasonality of births, and intervals between births. The pair was released in November 2009 on the campus of the University of São Paulo in Ribeirão Preto, São Paulo State, Brazil. Data on copulations were collected from January 2010 to March 2011 and from January 2012 to December 2014. Births were collected from January 2010 to December 2016. During the 5-year observation period, 25 copulations were recorded. Seven births were recorded over a period of 7 years, which included reproduction of the offspring of the translocated pair. Births occurred in the dry season between April and August. The interval between births was approximately 1 year. Our data provide insight into the reproduction of howler monkeys that have been translocated to a new habitat. Translocation can provide a valuable approach for rescuing or restoring Alouatta, whose populations have been detrimentally impacted by long-term habitat fragmentation.

Demography and life history of wild red titi monkeys (Callicebus discolor) and equatorial sakis (Pithecia aequatorialis) in Amazonian Ecuador: A 12-year study.

We investigated demographic patterns and life history traits from several groups of red titi monkeys (Callicebus discolor) and equatorial sakis (Pithecia aequatorialis) monitored throughout the first 12 years (November 2003 through May 2015) of an ongoing research project in the Yasuní National Park and Biosphere Reserve, Ecuador. The saki groups ranged in size between two and six individuals, comprising either one adult male and one adult female or multiple adult-sized males or females, plus immatures. Deviations from a pair-living structure resulted when two different daughters of the resident female grew up and successfully reproduced in their natal group and when an adult-sized male temporarily immigrated into the group when it already contained an adult male. The titi groups also ranged in size between two and six individuals, but almost exclusively lived in groups with one adult individual of each sex. No titi offspring were observed to breed in their natal groups, and both male and female offspring dispersed when they were between 2.1 and 5.0 years old. In both titi and saki groups, vacant breeding positions resulting from the disappearance of an adult group member were promptly occupied by immigrants of the same sex as the disappeared group member. We recorded nine saki and 28 titi births. Eighty-three percent of the titi births occurred between September and January, suggesting reproductive seasonality. The mean interbirth interval after an infant survived its first 6 months was 21.3 ± SE 1.9 months (N = 3) for sakis and 14.5 ± SE 1.5 months (N = 14) for titis. Saki infant survival was 70%, and juvenile survival 57%. Titi infant survival was 88%, and juvenile survival was 53%. This 12-year study provides important insights into the functioning and maintenance of pair-living and social monogamy in two little-known platyrrhine species.

Reproduction of the owl monkey (Aotus nancymai) (primates:Cebidae) in captivity.

There are few reports and poorly documented field studies about the reproductive biology of the owl monkey (Aotus spp.). Reproductive data were collected from a breeding colony of owl monkeys (Aotus nancymai) held at the Center for Reproduction and Conservation of Non-Human Primates in Iquitos, Peru, for the past 10 years. Seventy nine breeding pairs have produced 180 offspring in a period of 3,619 months, representing an average of about one offspring for every 20 months that a pair was housed together. Neonatal mortality in the first week was 7.1%. Litter size was almost one (99.4%). The mean age at first birth in a group of nine females born in captivity was 40.56 ± 7.82 (S.D.) months. The mean age of a group of 12 males born in the colony when their female mates produced offspring was 42.17 ± 10.73 (S.D.) months. Gestation length did not exceed 141 days. Interbirth interval averaged 12.72 months. A birth peak was observed from October to January. Breeding Aotus nancymai on a large scale in captivity is feasible.