The social mammal present complex and sophisticate vocal behavior, they are able to
send and receive precise information about the environment and the interactions of the
group. The order Rodentia, the biggest among mammals, has species that developed
wide vocal repertoire in order to intermediate both interspecific and intraspecific
relationships. During threatening context, some rodents emit specific vocalizations
classified as alarm calls, these calls allow the perception of the threat and the possibility
of subsequent reaction such as fight or scape. These reactions in the context of threat
provide to these rodent species an effective defense against predation. In this context,
we described and compared the acoustic parameter of the alarm call of the agouti
(Dasyprocta sp.) and the lowland paca (Cuniculus paca) using the sonographic analysis
of their vocalizations recorded in captivity. We realized the register of the agonistic
calls of 16 individuals of Dasyprocta sp. and 6 individuals of C. paca in the vivarium
placed in the Federal University of Para in a total of 85 minutes of recording.
We recorded alarm calls during the social interactions that happened in their
respective cages. The bioacoustics analysis of the 539 alarm calls of the agouti
demonstrate that the frequency bandwidth varies from 224 to 978 Hz and the duration is
898 ms. The 95 alarm calls of the lowland paca analyzed presented frequency
bandwidth that varied from 340 to 1280 Hz, the mean of the call’s duration was
1967 ms. The sound characteristics of these so called indicated that there is a
predominance of lower frequencies of the acoustic signal of the two species, but the
pacas can reach high and low frequencies much larger than the agoutis, and issue of longer
duration signals. The principal components analysis (PCA) revealed that the alarm calls
of both species are differentiated primarily by the maximum duration and frequency of
the beeps.
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