Acoustic data in four species of macaques

We provide comparative data on vocal signals in adult females of four
species of macaque : Tonkean macaques (Macaca tonkeana), crested macaques
(M. nigra), Japanese macaques (M. fuscata), and rhesus macaques (M.
mulatta). We distinguished three social contexts: agonistic, affiliative
and neutral. The agonistic context included aggression (supplantation,
lunge, chase, slap, grab, bite, facial threat display) and response to
aggression (aggression, avoidance, flight, crouch, submissive facial
displays). The affiliative context included affiliative behaviours
(approach, sitting in contact, social grooming, social play, grasp,
embrace, mount, affiliative facial display). In the neutral context, the
caller was not involved in a social interaction. We drew spectrograms
using the sofware Raven Pro v1.4’ (Cornell Lab of
Ornithology, www.birds.cornell.edu/raven) with a
256 fast Fourier transform length and a Hanning window.
With the same software, we measured the following variables: Duration:
duration from the beginning to the end of a call, in seconds; Q2 ratio:
ratio between duration that divides a call into two intervals of equal
energy and duration in percentage; Q1 frequency: value of the frequency
that divides a call into two intervals containing 25% and 75% of the
energy, in Herz; Q2 frequency: value of the frequency that divides a call
into two intervals of equal energy, in Herz; Q3 frequency: value of the
frequency that divides a call into two intervals containing 75% and 25% of
the energy, in Herz; Wiener’s aggregate entropy: degree of disorder (i.e.
noisiness) of the call, which uses the total energy in a
frequency bin over the entire call; Wiener’s average entropy:
mean of the mean entropies of the different time slices of a call. Our
objective was to compare the four species on tonal and atonal calls, so we
did not take into account the variables associated with fundamental
frequencies since they are absent in atonal calls.