Figure 2From: Context-specific close-range “hoo” calls in wild gibbons (Hylobates lar) Two scatter plots of functions 1 (intercall interval) and 2 (low frequency/delta frequency) as they explain the variation between the different hoo contexts in males (M) and females (F). ○ = big cat; □ = raptor; ● = group encounter ∆ = duet; ■ = group centroid.Back to article page