Science Advances

Supplementary Materials

This PDF file includes:

  • Legends for videos S1 to S5
  • Supplementary Methods
  • table S1. Source data for experiment 1: Marking behavior in relation to test and control variables.
  • table S2. Source data for experiment 2: Vocal and nonvocal behaviors of subjects per trial after seeing a snake model.
  • table S3. Experiment 2: Predictions for receiver knowledge (H1) and signaler habituation (H2) hypotheses.
  • table S4. Experiment 2: Control predictors have little influence on chimpanzee calling and marking behavior.
  • fig. S1. Typical scenario upon viper (B. rhinoceros) detection by chimpanzees.
  • fig. S2. Vipers photographed in the Budongo Forest and replica snake models used in the experiments.
  • References (52–55)

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Other Supplementary Material for this manuscript includes the following:

  • video S1 (.mp4 format). Western chimpanzees (Pan troglodytes verus) in the Tai National Park, Ivory Coast, see real, highly camouflaged rhinoceros viper (www.youtube.com/watch?v=AVXU9C-Oq2k; see fig. S3 for stills).
  • video S2 (.mp4 format). Experiment 1 with marking: Kato alert hoos and marks a gaboon viper model for an ignorant receiver with whom he shares a bond (Pan troglodytes schweinfurthii, Budongo Forest, Uganda).
  • video S3 (.mp4 format). Experiment 1 without marking: Squibbs alert hoos but does not mark a gaboon viper model for ignorant receivers with whom he does not share a bond (P. troglodytes schweinfurthii, Budongo Forest, Uganda).
  • video S4 (.mp4 format). Experiment 2: Rest hoo condition (P. troglodytes schweinfurthii, Budongo Forest, Uganda).
  • video S5 (.mp4 format). Experiment 2: Alert hoo condition (P. troglodytes schweinfurthii, Budongo Forest, Uganda).

Files in this Data Supplement: