Why do captive pied tamarins give birth during the day?

Abstract

Diurnal primates typically give birth at night, when it is presumed that they are safer at a very vulnerable time, and this is reflected in an overwhelmingly nocturnal pattern of delivery in most species of Callitrichidae. However, over half (51.1%) of 88 births to pied tamarins (Saguinus bicolor) at Durrell Wildlife Park occurred during the day (0800-1700), almost always in the afternoon. Nearly three quarters of breeding females (17/23) had at least one diurnal birth, including females from all generations in captivity from wild-caught to fifth captive-born generation, and from all six matrilines represented at Durrell. The proportion of diurnal births has remained relatively stable over time despite management changes. We used generalized linear mixed modeling to investigate several factors that we hypothesized could affect time of birth: maternal experience, season, female rearing history, and whether or not the group was on public display. We fitted all possible models to the data, but none explained more than 7.5% of the variation. Daytime delivery had few statistically significant detrimental effects, although infant survival was somewhat lower and parental rejection increased in diurnal births. Pied tamarins do not seem to fit any of the hypotheses previously put forward to explain exceptions to the typical primate circadian pattern of delivery. Zoo Biol. 35:487-494, 2016. © 2016 Wiley Periodicals, Inc.

Testing the weekend effect hypothesis: Time of day and lunar phase better predict the timing of births in laboratory‐housed primates than day of week

“…Not only was there no substantial variation throughout the week in the monkeys’ pattern of births, there was also no noticeable variation across the three genera in terms of the time of day that they gave birth: all the births occurred overnight, not during the day time. This parallels the behavior reported for many diurnal primates, which have been shown to give birth more frequently at nighttime than during the day (Bowden, Winter, & Ploog, ; Jolly, ; Price et al, ; Solanki & Zothansiama, ). However, and following our prediction, the nocturnal owl monkeys were more likely to give birth on bright nights.…”

“…This suggests that nighttime birthing patterns are not only favorable for diurnal monkeys in “a natural environment” ( sensu , Honnebier & Nathanielsz, ), but also for animals in a captive setting. Indeed, a recent review of callitrichid births in a zoo setting revealed that seven of the eight species studied preferentially gave birth during nighttime (the exception was Saguinus bicolor , Price et al, ).…”

“…Given these changes in personnel routine and activity during the week, for our first aim we predicted that, if there is a true weekend effect, there should be a greater number of live births recorded during weekend days than weekdays due to the reduction in disturbances on Saturdays and Sundays. For our second aim, given that primates, and especially nocturnal ones, are more active during full‐moon nights (e.g., Erkert, ; Fernandez‐Duque & Erkert, ), and captive primates are more likely to give birth at night (Price, Payne, & Wormell, ), we predicted that the monkeys, especially the owl monkeys, would be more likely to give birth when there was increased night light.…”

Individual, social, and environmental factors affecting salivary and fecal cortisol levels in captive pied tamarins (Saguinus bicolor)

“…Pied tamarins are also behaviorally different from other callitrichids in some respects, e.g. in frequently giving birth during the day (Price, Payne & Wormell, 2016). Thus, to adapt management and improve welfare, as much species-specific information as possible is needed about the extent to which pied tamarins experience stress from various sources, as assumptions based on information from other species may not be valid.…”

“…They may therefore be more stressed by contact with people. As hand-reared female pied tamarins never successfully rear their own infants (Price et al, 2016), whereas a hand-reared male did become a competent parent (pers. obs.…”