Homophily in social and demographic traits predict association patterns in female western and mountain gorillas
Data files
Oct 16, 2024 version files 85.05 KB
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Model1.csv
18.52 KB
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Model2.csv
38.86 KB
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Model3.csv
14.01 KB
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Model4.csv
9.36 KB
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README.md
4.30 KB
Abstract
Affiliative relationships are a hallmark of social relationships in gregarious mammals, but what drives variation of association patterns remain to be investigated. Gorillas, who exhibit female dispersal, provide an interesting counterpoint to female philopatric species to examine the factors influencing variation in association patterns. We examined demographic and social factors that may predict association patterns of female western (Gorilla gorilla gorilla; Loango, Gabon) and mountain gorillas (Gorilla beringei beringei; Bwindi, Uganda). We looked at dyadic and individual strength scores of social proximity data (37 group-years). For individual female gorillas, high dominance rank increased association scores and being newly emigrated decreased them. For dyads, higher mean dominance rank, and both partners having a dependant infant increased association scores, whereas a partner being newly emigrated decreased association scores. Further analysis of time-matched birth and emigration events confirmed the temporal nature of these associations. Overall, female gorilla association patterns show flexibility in association strength based on real time contingencies, namely social and demographic traits. Our results suggest that affiliative relationships in species with female secondary dispersal are governed by homophily like that of modern humans. Understanding the female gorilla social structure can enhance our knowledge of the evolutionary origins of sociality.
https://doi.org/10.5061/dryad.k3j9kd5hq
Description of the data and file structure
Files are stored as .csv files. There are 4 files in total each referring to models 1-4 of the analysis.
Files and variables
File: Model4.csv
Description: Data to run the time-matched analysis for female gorilla dyadic immigration status - model 4.
Variables
- Group: Gorilla group ID - ATA, KYA, ORU, BIT.
- ID: Female gorilla ID - first dyad member.
- ID2: Female gorilla ID - second dyad member.
- Strength: Association strength score: the number of times both individuals were within 5m of each other divided by the total number of scans that each was the focal animal.
- year: Year of data collection.
- Event: Was the dyad one where one dyad member was an immigrant female Y = Yes, N = No.
- TimePeriod: Time period of data collection in years related to the immigration event: 0 = year of immigration, 1, 2, 3 ,4 = 1, 2, 3, 4 years after the event.
- DyadID1: Female dyad ID.
File: Model3.csv
Description: Data to run the time-matched analysis for female gorilla dyadic birth status - model 3.
Variables
- Group: Gorilla group ID - ATA, KYA, ORU, BIT.
- ID: Female gorilla ID - first dyad member.
- ID2: Female gorilla ID - second dyad member.
- Strength: Association strength score: the number of times both individuals were within 5m of each other divided by the total number of scans that each was the focal animal.
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year: Year of data collection.
- TimePeriod:Time period of data collection in years related to the birth event: 0 = year of birth, -2,-1, 1, 2, = -2, -1, 1, 2, years before or after the event.
- Event: Was the dyad one where both dyad member had a dependant infant Y = Both, N = None/One.
- DyadID1: Female dyad ID.
File: Model1.csv
Description: Data to run the individual level analysis for predictors of female gorilla association scores- model 1.
Variables
- Group: Gorilla group ID - ATA, KYA, ORU, BIT.
- ID: Female gorilla ID.
- Strength: Association strength score: the total number of times each individual was observed within a 5m radius of another female group member per year, controlling for the total number of scans collected per female.
- Year: Year of data collection.
- Infant: Did the female have an infant that year - yes/no.
- Immigrant: Was the female a new immigrant that year - yes/no.
- last.year: Was it the females last year in the group - yes/no.
- Tenure: Z-transformed female residency length in days.
- OrdRank: Z-transformed females ordinal rank position.
- ZGrpS: Z-transformed group size.
- SBChange: Was there a new alpha male that year - yes/no.
- ZFem: Z-transformed female number.
File: Model2.csv
Description: Data to run the dyadic level analysis for predictors of female gorilla association scores- model 2.
Variables
- Group: Gorilla group ID - ATA, KYA, ORU, BIT.
- ID: Female gorilla ID - first dyad member.
- ID2: Female gorilla ID - second dyad member.
- Strength: Association strength score: the number of times both individuals were within 5m of each other divided by the total number of scans that each was the focal animal.
- Year: Year of data collection.
- Dyad_ID: Female dyad ID.
- SB_New: Was there a new alpha male that year - yes/no.
- Infant1: Did one, both or neither female dyad member have an infant - both/one/none.
- New_Dyad: Was one female dyad mamber new to the group that year - yes/no.
- ZGp: Z-transformed group size.
- ZFemNum: Z-transformed female number.
- ZRankAve: Z-transformed average dominance rank for each dyad.
Code/software
Data are in .csv files so can be accessed via any programme to open .csv files e.g., excel or numbers.
The R markdown file contains 4 sections to run the four models.
The code to run the analysis was done in R (version 4.3.1).
Packages used for each analysis are listed with in the R markdown file
Access information
Other publicly accessible locations of the data:
- No publicly accessible locations.
Data was derived from the following sources:
- Data was not derived from any other sources.
This data relates to data collected on mountain and western gorilla females association patterns and the predictor variables. Continuous variables have been z-transformed. Please refer to the manuscript for full details of the methods.