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Figure S1. Different scenarios describing the cumulative distribution of facial expressions or types of facial expressions through recording time.

Figure S2. Cumulative number of facial expressions in different individuals as a function of the recording time. The empirical data is given by a blue thick line and simulated data are given by 25 red thin lines in each case. Detailed information contains the name of the individual, the Genus, and the lambda parameter defining the stochastic Poisson Process, estimated using maximum likelihood methods.

Figure S3. Number (blue line) and type (repertoire—red line) of the individuals Spike (Symphalangus), Dorian (Nomascus), and Bert (Hylobates) Versus Recording Time.

Figure S4. Single values used for generating the monogamy indices plotted (EPC = extra pair copulation; PA = polyandry; PG = polygyny; Pd = proximity at day; Pn = proximity at night; D = desertion; Gc = group composition (i.e., more than two adult individuals); PC = paternal care) for all five species (NS = Nomascus siki, NG = Nomascus gabriellae, HL = Hylobates lar, HP = Hylobates pileatus, SS = Symphalangus syndactylus). A: All values (including “no information” = 0.5). B: Exclusion of “no information.”

Figure S5. Example how the information from the literature was ranked to create the values of the monogamy index. Values 10% and 13% ranked from the literature (see Table SI in Supplementary Material 2) to values of the indices. If no information is provided, the variable given for this variable is “0.5.” The variables can increase or decrease beginning from this value, and therefore the index reflects the information we have about monogamy rather than the actual monogamy level (this index should not be interpreted as if a value of 1 represents fully monogamous). If we consider “0” in the index as “least monogamous,” then the higher the percentage, for example, extra pair copulation is, the closer it is to the value “0,” starting from 0.5 (=0%). 10% in the direction to 100% (=0 in the Index) resembles 0.45 in the Index. Quantitative information (yes/no) has been transformed into numbers, depending on the strength/quantity of information found (“yes, not much (=0.67)” is ranked less strong than “yes (=0.83)” and numbers depend on whether information is in direction favoring monogamy (=1) not (=0) etc.).

Table SI. Group Composition of the Individuals

Table SII. Individual Recording Times and Average Recording Time Per Genera

Table SIII. Detailed Description of the Observed Action Units and Action Descriptors

Table SIV. Values for Each of the Variables Reflecting Monogamy for Each of the Five Species

ajp22255-sm-0001-SuppData-S2.docx91KTable SI. Information From the Literature for Each of the Five Species and Values for Ranking Them to Create the Indices

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