Factors of influence and social correlates of parturition in captive Campbell's monkeys: Case study and breeding data

Abstract

How nonhuman primates deal with birth, at the moment of delivery, and during the following days, remains poorly explored because of the unpredictability of this event, particularly for forest-dwelling arboreal species. Available studies highlight intra- and interspecific variation which suggest flexibility of the timing of delivery, of behavior associated with labor contractions and parturition, and the social context and ambient noise surrounding delivery. Here, we present the findings of a two-decade survey of reproduction in a population of captive Campbell's monkeys. Analysis of 34 births (with a female-biased sex ratio) showed that deliveries occurred systematically at night and more frequently during week-ends and in fall (September-November). This suggests the existence of both circadian and infradian biological rhythms. We present the first detailed description of a birth for this species and its short-term social consequences. In line with previous findings for other monkeys and apes, labor (estimated by unusual stretching postures) and parturition were rapid, and delivery occurred in a clear social and vocal context. During the following days, the new mother became the center of attention of for young (kin and non-kin) females and rose through the hierarchy. We discuss socio-ecological factors, notably captivity conditions and the high degree of tolerance in the species' social system, and confirm the existence of both "rigidity" and "flexibility" in the primates' adaptive reproductive strategies.

Zoo‐housed mammals do not avoid giving birth on weekends

“…The results from the laboratory studies are also not consistent. Of the three primate colonies examined by McGrew and McLuckie (1984), only one showed the weekend effect and both this colony and the one examined by Lemasson et al (2017) had low sample sizes ( n < 50). Of the two studies that had larger sample sizes, only the one by Alford et al (1992) showed a weekend effect.…”

“…They attributed this pattern to the stressful effects of routine laboratory procedures occurring during the week, which were greatly reduced on weekends. Finally, in a laboratory colony of Campbell's monkeys ( Cercopithecus campbelli ), analysis of 34 births again showed that significantly more births occurred on weekends than during the week, and this also was attributed by the authors to the disruption caused by laboratory procedures during the week (Lemasson et al, 2017).…”

The continuing misuse of null hypothesis significance testing in biological anthropology

“…In conventional usage, they are considered to contradict each other. For example, Lemasson, Jubin, Bec, and Hausberger (, p. 4), examining behavior of Campbell's monkeys, conclude that following delivery of an infant, social play by the mother decreased ( Z = 2.03, p = 0.043), but call exchanges “did not” ( Z = 1.72, p = 0.09).…”