Post-release survival and behavior of rehabilitated and released vervet monkeys (<em>Chlorocebus pygerythrus rufoviridis</em>) in Malawi

Published research on primate rehabilitation and release (R&R) is limited, and studies suggest that released mortality is generally high. We investigated factors affecting the survival and behavior of a rehabilitated troop of vervet monkeys (Chlorocebus pygerythrus rufoviridis) released into Kasungu National Park in Malawi in 2016 by the Lilongwe Wildlife Trust (LWT). Estimated troop survival nine months after release was 45% when dispersing-age male disappearances were considered emigrations, which is comparable to other vervet monkey R&R. Using a combination of linear modeling, survival analysis, and social network analysis, we considered social rank, forest strata use, anti-predator behavior, troop cohesion and social connectedness, and behavioral diversity across release phases as potential factors influencing survival. Our results suggest that socially connected individuals and juveniles were more likely to survive, with these factors more significant than sex, social rank, and anti-predator behavior. Unexpectedly, anti-predator behavior significantly decreased after release, which may be a factor linked to increased predation. Also unexpectedly, behavioral diversity decreased post-release, likely due to a significant increase in locomotion upon release and limitations with our ethogram. The observed mortality patterns suggest that R&R troops may benefit from pre-release training with platform feeders that encourage canopy use. When possible, individual life history data (e.g., captive-born, orphaned) should be collected at rescue and rehabilitation stages to help inform caretakers of unique needs. LWT’s extensive pre- and post-release monitoring provides vital insights into the factors influencing this troop’s survival. We urge other rehabilitation centers to follow this strategy to improve R&R programs. # Post-release survival and behavior of rehabilitated and released vervet monkeys (*Chlorocebus pygerythrus rufoviridis*) in Malawi We have submitted our pre-release raw data (**2016_pre-release_cont_FULL.csv, 2016_pre-release_focals_FULL.csv, Pre-release_Social_Proximity.csv**), and post-release raw data (**2016_post-release_cont_FULL.csv, 2016_post-release_focals_FULL.csv, 2016_post-release_focals_SURV.csv, Post-release_Social_Proximity_TOTALS.csv, Post-release_Social_Proximity.csv**). Blank cells are noted below for each column (when applicable). ## Descriptions ### 2016_pre-release_cont_FULL.csv (Continuous behavioral data) * *obsid*: observation ID (not included in analyses) * *DAY, MONTH, YEAR, date*: Date of observation * *hour, minute, :, time*: time of observation (contains blanks - column not included in analyses) * *dayperiod*: AM/PM of observation (not included in analyses) * *focal reference*: reference number * *observer1, observer2*: observer(s) recording data (not included in analyses) * *weather, temp*: weather and temperature on data of recording (contains blanks - column not included in analyses) * *FOCAL ID*: unique focal ID for each monkey * *sex*: sex (M/F) of each monkey (contains 1 blank cell) * *age*: age (Adult - A; SA - subadult; J - juvenile; I - infant) * *sampleperiod*: sample period of observation (not included in analyses) * *focalmin*: minute of each observation in the observation period (contains blanks - column not included in analyses) * *BEHAVIOUR*: unique behavior code * *ASSOCIATION*: unique vervet ID for individual associated with focal vervet at that focal minute (contains blanks when focal vervet is not associated with another individual) * *conflict outcome*: outcome of either 1 - focal acts aggressively or receives aggression and WINS or 2 - focal acts aggressively or receives aggression and LOSES (contains blanks when focal vervet did not engage in conflict with another individual) * *G.P.S. Location, NoteS*: (contains blanks - columns not included in analyses) ### 2016_pre-release_focals_FULL.csv (Focal follow behavioral data) * *obsid*: observation ID (not included in analyses) * *treat*: treatment period, pre-release (not included in analyses) * *DAY, MONTH, YEAR, date*: Date of observation * *projectmonth*: Month data was collected (not included in analyses) * *block*: block of data collection (not included in analyses) * *hour, minute, :, time*: time of observation (contains blanks - column not included in analyses) * *dayperiod*: AM/PM of observation (not included in analyses) * *focal reference*: reference number * *observer1, observer2*: observer(s) recording data (contains blanks - column not included in analyses) * *weather, temp*: weather and temperature on data of recording (contains blanks - column not included in analyses) * *FOCAL ID*: unique focal ID for each monkey * *sex*: sex (M/F) of each monkey * *age*: age (Adult - A; SA - subadult; J - juvenile; I - infant) * *sampleperiod*: sample period of observation (not included in analyses) * *focalmin*: minute of each observation in the observation period * *BEHAVIOUR*: unique behaviour code (contains 2 blank cells) * *BEHAVIOUR 2*: unique behaviour code 2 when two behaviours can occur simultaneously (e.g., vigilance & contact; contains blanks when the focal individual doesn't have a second behaviour). * *ASSOCIATION*: unique vervet ID for individual associated with focal vervet at that focal minute (contains blanks when focal vervet is not associated with another individual) * *foodtype*: (contains blanks - column not included in analyses) * *canopy*: The canopy position and corresponding height distinction vary based on the vertical size of the tree; G= ground; LC= lower third of tree canopy; MC= middle third of tree canopy; TC= top third of tree canopy, MMS= manmade structure; NS= natural structure. Height category 1= <5m off of the ground; 2= 5-10m off of the ground; 3= 10-20m off of the ground (contains blanks when focal vervet is out of sight (OS)) * *PLANT SPECIES, PLANT SPECIES SAT ON, G.P.S. Location, NOteS*: (contains blanks - columns not included in analyses) ### Pre-release_Social_Proximity.csv * *Day, Month, Year*: Date of observation * *Hour, Minute*: time of observation * *AM/PM*: AM or PM of observation (not included in analyses) * *FOCAL REFERENCE*: reference number * *OBSERVER 1, OBSERVER 2*: observer(s) recording data (not included in analyses) * *WEATHER, TEMP*: weather and temperature on the data of recording (not included in analyses) * *Focal ID*: unique focal ID for each monkey * *Sex*: sex (M/F) of each monkey * *Age*: age (Adult - A; SA - subadult; J - juvenile; I - infant) * *FOCAL PERIOD*: period of focal observation * *amount*: (contains blanks - column not included in analyses) * *Focal Minute*: minute of each observation in the observation period (not included in analyses) * *Association*: unique monkey ID for the individual associated with the focal individual at that focal minute * *Proximity Code*: Each visible (to the observer) monkey is placed into an approximate distance category from the focal individual, based on the observer’s visual estimate. Proximity code corresponds to distance: 1 = <1m, 2 = 1- 5m, 3 = 5-10m, 4 = >10m (contains blanks when Association column is OS (out of sight). ### 2016_post-release_cont_FULL.csv (Continuous behavioral data) * *DAY, MONTH, YEAR*: Date of observation * *TIME (HOUR), TIME (MINUTE)*: Time of observation (not included in analyses) * *FOCAL REFERENCE CODE*: reference number * *OBSERVER 1, OBSERVER 2*: observer(s) recording data (contains blanks - column not included in analyses) * *WEATHER, TEMP*: weather and temperature on the data of recording (contains blanks - column not included in analyses) * *FOCAL ID*: unique focal ID for each monkey * *SEX*: sex (M/F) of each monkey * *AGE*: age (Adult - A; SA - subadult; J - juvenile; I - infant) * *ESTRUS*: estrus stage of female vervet (contains blanks - column not included in analyses) * *FOCAL PERIOD*: period of focal observation (not included in analyses) * *FOCAL MINUTE*: minute of each observation in the observation period (not included in analyses) * *BEHAVIOUR*: unique behavior code * *ASSOCIATION*: unique vervet ID for individual associated with focal vervet at that focal minute (contains blanks when focal vervet is not associated with another individual) * *CONFLICT OUTCOME*: outcome of either 1 - focal acts aggressively or receives aggression and WINS or 2 - focal acts aggressively or receives aggression and LOSES (contains blanks when focal vervet did not engage in conflict with another individual) ### 2016_post-release_focals_FULL.csv (Focal follow behavioral data) * *RELEASE*: release stage (pre or post) * *DAY, MONTH, YEAR*: Date of observation * *TIME (HOUR), TIME (MINUTE)*: Time of observation (not included in analyses) * *AM/PM*: AM or PM of observation (not included in analyses) * *FOCAL REFERENCE*: reference number * *OBSERVER 1, OBSERVER 2*: observer(s) recording data (contains blanks - column not included in analyses) * *WEATHER, TEMP*: weather and temperature on the data of recording (contains blanks - column not included in analyses) * *FOCAL ID*: unique focal ID for each monkey * *SEX*: sex (M/F) of each monkey * *AGE*: age (Adult - A; SA - subadult; J - juvenile; I - infant) * *ESTRUS*: estrus stage of female vervet (contains blanks - column not included in analyses) * *FOCAL PERIOD*: period of focal observation (not included in analyses) * *FOCAL MINUTE*: minute of each observation in the observation period (not included in analyses) * *BEHAVIOUR*: unique behaviour code (contains 1 blank) * *BEHAVIOUR 2*: unique behaviour code 2 when two behaviors can occur simultaneously (e.g., vigilance & contact; contains blanks when the focal individual doesn't have a second behaviour). * *ASSOCIATION*: unique vervet ID for individual associated with focal vervet at that focal minute (contains blanks when focal vervet is not associated with another individual) * *FOOD TYPE*: type of food eaten by focal vervet monkey (contains blanks - column not included in analyses) * *POSITION IN CANOPY*: The canopy position and corresponding height distinction vary based on the vertical size of the tree; G = ground; LC = lower third of tree canopy; MC = middle third of tree canopy; TC = top third of tree canopy; MMS = manmade structure; NS = natural structure. Height category 1= <5m off of the ground; 2= 5-10m off of the ground; 3= 10-20m off of the ground (contains blanks when focal vervet is out of sight (OS)) * *PLANT SPECIES SAT ON*: (contains blanks - column not included in analyses) ### 2016_post-release_focals_SURV.csv (Focal follow behavioral data) * *RELEASE*: release stage (pre or post) * *DAY, MONTH, YEAR*: Date of observation * *TIME (HOUR), TIME (MINUTE)*: Time of observation (not included in analyses) * *AM/PM*: AM or PM of observation (not included in analyses) * *FOCAL REFERENCE*: reference number * *OBSERVER 1, OBSERVER 2*: observer(s) recording data (contains blanks - columns not included in analyses) * *WEATHER, TEMP*: weather and temperature on the data of recording (contains blanks - columns not included in analyses) * *FOCAL ID*: unique focal ID for each monkey * *SEX*: sex (M/F) of each monkey * *AGE*: age (Adult - A; SA - subadult; J - juvenile; I - infant) * *ESTRUS*: estrus stage of female vervet (contains blanks - column not included in analyses) * *FOCAL PERIOD*: period of focal observation (not included in analyses) * *FOCAL MINUTE*: minute of each observation in the observation period (not included in analyses) * *BEHAVIOUR*: unique behaviour code (contains 1 blank cell) * *BEHAVIOUR 2*: unique behaviour code 2 when two behaviours can occur simultaneously (e.g., vigilance & contact; contains blanks when the focal individual doesn't have a second behaviour). * *ASSOCIATION*: unique vervet ID for individual associated with focal vervet at that focal minute (contains blanks when focal vervet is not associated with another individual) * *FOOD TYPE, FOOD TYPE 2*: type of food eaten by focal vervet monkey (contains blanks - columns not included in analyses) * *POSITION IN CANOPY*: The canopy position and corresponding height distinction vary based on the vertical size of the tree; G = ground; LC = lower third of tree canopy; MC = middle third of tree canopy; TC = top third of tree canopy; MMS = manmade structure; NS = natural structure. Height category 1= <5m off of the ground; 2= 5-10m off of the ground; 3= 10-20m off of the ground (contains blanks when focal vervet is out of sight (OS)) * *Position2, Position3*: extra canopy position columns (all blanks - not included in analyses) * *PLANT SPECIES, PLANT SPECIES SAT ON, G.P.S. Location, NOtes*: (contains blanks - columns not included in analyses) * *Date End*: the date the vervet monkey was declared dead, disappeared, emigrated, or the end of the study (blanks when focal ID is CI, PA, or HO, which are wild males not included in survival analyses) ### Post-release_Social_Proximity_TOTALS.csv * *Day, Month, Year*: Date of observation * *Hour, Minute*: time of observation * *AM/PM*: AM or PM of observation (not included in analyses) * *FOCAL REFERENCE*: reference number * *OBSERVER 1, OBSERVER 2*: observer(s) recording data (contains blanks - column not included in analyses) * *WEATHER, TEMP*: weather and temperature on the data of recording (contains blanks - column not included in analyses) * *Focal ID*: unique focal ID for each monkey * *Sex*: sex (M/F) of each monkey * *Age*: age (Adult - A; SA - subadult; J - juvenile; I - infant) * *ESTRUS*: estrus stage of female vervet (contains blanks - column not included in analyses) * *FOCAL PERIOD*: period of focal observation (not included in analyses) * *amount prox scans*: number of proximity scans (contains blanks - column not included in analyses) * *Focal Minute*: minute of each observation in the observation period (contains blanks - column not included in analyses) * *Association*: unique vervet ID for the individual associated with the focal vervet at that focal minute * *Proximity Code*: how close the focal vervet monkey is to the association monkey (contains blanks when the Association column is OS (out of sight)) ### Post-release_Social_Proximity.csv * *Day, Month, Year*: Date of observation * *Hour, Minute*: time of observation * *AM/PM*: AM or PM of observation (not included in analyses) * *FOCAL REFERENCE*: reference number * *OBSERVER 1, OBSERVER 2*: observer(s) recording data (contains blanks - column not included in analyses) * *WEATHER, TEMP*: weather and temperature on the data of recording (contains blanks - column not included in analyses) * *Focal ID*: unique focal ID for each monkey * *Sex*: sex (M/F) of each monkey * *Age*: age (Adult - A; SA - subadult; J - juvenile; I - infant) * *ESTRUS*: estrus stage of female vervet (contains blanks - column not included in analyses) * *FOCAL PERIOD*: period of focal observation (not included in analyses) * *amount prox scans*: number of proximity scans (contains blanks - column not included in analyses) * *Focal Minute*: minute of each observation in the observation period (contains blanks - column not included in analyses) * *Association*: unique vervet ID for the individual associated with the focal vervet at that focal minute * *Proximity Code*: Each visible (to the observer) monkey is placed into an approximate distance category from the focal individual, based on the observer’s visual estimate. Proximity code corresponds to distance: 1 = <1m, 2 = 1- 5m, 3 = 5-10m, 4 = >10m (contains blanks when Association column is OS (out of sight)) * *number, G.P.S. Location*: (contains blanks - column not included in analyses) ## Code/Software R is required to run *April2026_FinalCode_LWTVervetRelease.R*; R version 3.6.1 was used, and the script was created in RStudio using version 2023.6.1. Annotations are provided throughout the script.