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An early-life challenge: becoming an older sibling in wild mandrills

Cite this dataset

Delaunay, Axelle et al. (2024). An early-life challenge: becoming an older sibling in wild mandrills [Dataset]. Dryad.


In monotocous mammals, most individuals experience the birth of a younger sibling. This period may induce losses in maternal care and can be physiologically, energetically and emotionally challenging for the older sibling, yet has rarely been studied in wild primates. We used behavioural data collected from a natural population of mandrills to investigate changes in maternal care and mother-juvenile relationship throughout the transition to siblinghood (TTS), by comparing juveniles who recently experienced the birth of a younger sibling, to juveniles who did not. We found that the TTS was associated with an abrupt cessation of the weaning process for the juvenile, and to a decrease in maternal affiliation. Juveniles’ reactions were sex-specific, as males associated less with their mother, while females tended to groom their mother more often after the birth of their sibling. Despite the substantial loss of maternal care juveniles did not show an increase in conflict or anxiety-related behaviours. This study contributes to explain why short interbirth intervals often pose a risk to juveniles’ survival in monotocous primates. Our results contrast existing studies and further highlights the importance of examining the TTS in species and populations with various life histories and ecologies.

README: An early-life challenge: becoming an older sibling in wild mandrills

Description of the data and file structure

Data used to run all models presented in the article can be found in "Data_TTSMandrills_vGitHub.xlsx".The file contains several sheets, each labeled with the model number for which the dataset in the given sheet should be used. The last sheet contains a legend of the variables in each dataset. Note that in the R code, the different datasets are loaded as individual .csv files, so each excel sheet will need to be converted into a .csv file before running the code. 

The code used to run the models can be found in "Script_TTSmandrills_Analyses_vGitHub.R" (Zenodo)

Sharing/Access information

All data and code can also be found here:


French National Centre for Scientific Research, Award: SEEG Lekedi, CNRS ECologie & Environnement

Agence Nationale de la Recherche, Award: ANR SLEEP-17-CE02-0002

Agence Nationale de la Recherche, Award: ANR ERS-17-CE02-0008