Figure 4

The exponents of different callings changed transiently in response to the social context (a) and the access to water (b). (a) Comparison of median empirical cumulative distribution functions (<eCDF>) between the inter-event intervals (τ) of “stack” calls during cohabitation (coh) and separation (sep). After limiting the social input to the auditory cues, the exponents (α) of reactive female (“m-f”) callings (p _m-f  = 0.039, n = 8) and reactive male (“f-m”) callings (p _f-m  = 0.027, n = 8) decreased while this did not change the exponents of self-contained female (“f-f”) and male (“m-m”) callings (p > 0.7, n = 8). (b) Comparison of <eCDFs> between the situations before, during and after removal of water. Removing water from males (wr male) increased the exponents (α) of self-contained male (“m-m”) callings (p _m-m  = 0.023, n = 7). Removing water from females (wr female) increased the exponents of self-contained male (“m-m”) callings (p _m-m  = 0.016, n = 7), of reactive female (“m-f”) callings (p _m-f  = 0.016, n = 7) and of reactive male (“f-m”) callings (p _f-m  = 0.008, n = 7). The other modes of callings remained unchanged (p > 0.050, n = 7). The exponents of base line and recovery were similar for all four modes of callings (p > 0.100, n = 7, recovery data are not shown on the ladder plots). n.s. and * indicate non-significant and significant, respectively. P(τ): the cumulative distribution of the inter-event intervals; τ (s): the inter-event intervals in seconds.