Seasonal patterns of infant mortality in wild Sanje Mangabeys, Cercocebus sanjei

McCabe, Grainne; Fernandez, David

Abstract

Infant mortality is a life history trait that is also a fundamental factor influencing population growth, thereby directly impacting the population viability of primate species. This study examines the distribution of infant mortality for one of the world’s most threatened primates, the Endangered Sanje mangabey, Cercocebus sanjei, endemic to the Udzungwa Mountains, Tanzania. Data collected over 40 continuous months (August 2008 – November 2011) are analyzed to assess patterns of infant mortality in relation to seasonality of ecological variables. Censuses conducted during monthly group follows recorded 35 live births during the study period, plus 6 born just prior to data collection commencing: 23 females, 16 males and 2 of undetermined sex. The survival probability for these infants combined is 60.2% (27 survived and 14 died before reaching one year of age). The mean annual infant mortality of 39.8 4.1%, is at the higher end of what has been described for other cercopithecine populations. All infant deaths occurred within the dry season (June – October), though most (64%, or 9 of 14) were highly clustered within the early dry season (June to August), a period coinciding with an initial drop in fruit production and a peak in tick infestation among adult females. Six of the infants (67%, or 6 of 14) that died were conceived in the previous dry season and born in the wet season; our previous work has demonstrated that this is considered ‘out-of-phase’ with the optimal conceptive timing for the species. These six infants represent a 67% mortality rate for dry season conceptions. Previous studies in this species have demonstrated that timing conception with peak food abundance can influence infant survival. We also suggest that tick-borne disease, prevalent in the Udzungwa region, should be further studied as it could be a factor impacting infant mortality in the Sanje mangabey and may be interacting with a decrease in nutritional intake during the early dry season.

• Peer Reviewed: Not Peer Reviewed
• Pages: 57-72
• Series Title: Developments in Primatology: Progress and Prospects
• Book Title: Primate Life History, Sex Roles, and Adaptability: Essays in Honour of Linda M. Fedigan
• ISBN: 9783319982847
• DOI: https://doi.org/10.1007/978-3-319-98285-4_4
• Keywords: Cercocebus sanjei, infant survivorship, disease, ectoparasites, seasonality
• Public URL: https://uwe-repository.worktribe.com/output/875032
• Publisher URL: https://doi.org/10.1007/978-3-319-98285-4_4