DOI: 10.5061/dryad.6q573n68n
title: Data from: Wild chimpanzees (Pan troglodytes schweinfurthii) use tools to access out of reach water

description: The use of tools to drink water is well-documented in wild chimpanzees,
 but the specific function of this behavior is unclear. Here we use a large
 dataset of drinking behaviors spanning 14 years of observation from the
 Kanyawara community of chimpanzees living in Kibale National Park, Uganda,
 in order to test two possible functions of leaf-sponges and other drinking
 tools. On the one hand, chimpanzees may use tools to access water that is
 hard to reach, which predicts that chimpanzees will preferentially use
 tools to drink at tree holes and crevices compared to all other locations.
 Conversely, chimpanzees may use these tools to filter stagnant water, in
 which case they would use tools more often at holes and puddles compared
 to running water sources (e.g., streams). We compared both likelihood of
 using a tool to drink at different locations, as well as overall rates of
 drinking, and found chimpanzees in this community most often drink from
 streams without tools. However, when they do use tools, they
 preferentially do so to drink at tree holes. Given known age and sex
 effects on tool use in chimpanzees, we also examined demographic variation
 in drinking tool use to understand the emergence of this behavior. While
 females use tools more often than males overall—in part driven by
 differences in drinking rates at different locations—both males and
 females use tools more frequently at tree holes than other locations when
 they do drink there. Finally, comparisons by age indicate that this
 selectivity strengthens over development with older chimpanzees showing a
 more pronounced effect of using tools more often at tree holes, suggesting
 that younger chimpanzees may exhibit exploratory tool-use behavior. These
 results pinpoint the specific function of tool use during drinking and
 further suggest that even simple tools may require learning for use in
 appropriate contexts.
description: # Wild chimpanzees (Pan troglodytes schweinfurthii) use tools to access
 out of reach water Dataset DOI:
 [10.5061/dryad.6q573n68n](10.5061/dryad.6q573n68n) ## Description of the
 data and file structure This data set consists of two files (.xlsx format)
 with the data for the different sets of analyses reported in this work.
 For each task, there is a key tab in the file defining each variation
 reported in the main data tab. The two files are: 1\. Drinking Events:
 each row in this file is the record of a discrete drinking event where
 chimpanzees did or did not use a tool to drink. Additional variables
 include the demographic characteristics of chimpanzee (age and sex); the
 year and month of the event; and the location of the drinking event. Some
 analyses with this dataset used only individuals over age 5 years
 (juvenile and adult cohorts). 2\. Drinking Rates: each row in this file is
 the annual drinking rate for a given chimpanzee a different locations;
 rates were calculated as count of drinking at a particular location
 divided by annual observation effort in hours and chimpanzees had to be
 observed for at least 50 total hours in a given year to be included.
 Additional variables include the demographic characteristics of chimpanzee
 (age and sex); and the year of observation. ### Files and variables ######
 Files * MacKenzie_etal_Chimpanzee_Drinking_Events.xlsx: this file contains
 analyzed drinking events from the study period *
 MacKenzie_etal_Chimpanzee_Drinking_Rates.xlsx: this file contains annual
 drinking rates for individual chimpanzees ###### Variables: drinking
 events | ***Variable*** | ***Description*** | | :------------- |
 :----------------------------------------------------------------------------------------------------------------------------------------------------------- | | Month | Month of drinking event | | Year | Year of drinking event | | Chimp\_ID | Number indicating each subject's unique identity | | Age | Age of chimpanzee at the time of the event in years | | Sex | Sex of the chimpanzee (M = male, F = female) | | Cohort | Categorical age cohort of the chimpanzee (infants under 5, juveniles 5-10 years, and adults) | | Tool\_Use | Whether the chimpanzee used a tool or not to drink in that event (1 = yes, 0 = no) | | Method\_cat | Method of drinking (no tool; leaf sponge tool; or other type of tool) | | Location\_cat | Whether the drinking event occurred at a stream; a puddle (drinking from ground or animal footprint); or a hole (drinking from a tree hole or tree buttress) | ###### Variables: drinking rates | ***Variable*** | ***Description*** | | :-------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Chimp\_ID | Number indicating each subject's unique identity | | Year | Year of data | | Sex | Sex of chimpanzee (F = female, M = male) | | Age | Age of subject that year in years | | DrinkRate | Rate of observed drinking at any location (also includes unknown or rare locations; rate calculated as count of observed drinking instances that year / hours of annual observation effort; observation effort had to exceed 50 hours of annual observation to be included). | | StreamDrinkRate | Rate of observed drinking at streams (rate calculated as count of observed drinking instances that year / hours of annual observation effort; observation effort had to exceed 50 hours of annual observation to be included). | | HoleDrinkRate | Rate of observed drinking at holes (includes both tree holes and tree buttresses; rate calculated as count of observed drinking instances that year / hours of annual observation effort; observation effort had to exceed 50 hours of annual observation to be included). | | PuddleDrinkRate | Rate of observed drinking at puddles (includes ground puddles and puddles formed in animal footprints; rate calculated as count of observed drinking instances that year / hours of annual observation effort; observation effort had to exceed 50 hours of annual observation to be included). | ## Code/software All analyses were conducted in R; see manuscript for detailed information.