Development of vocalizations in a fossorial rodent (Ctenomys sp.)

AMAYA JUAN PABLO; ARETA IGNACIO

Murnau

Congreso; XXV International Bioacoustics Congress; 2015

Ctenomys are highly vocal subterranean rodents endemic to South America. Acoustic communication is an integral part of their behavior and they exhibit a remarkable vocal repertoire of airborne signals. The S-type vocalizations are territorial and/or warning long-range signals conformed by two parts: Part 1 consists on a variable number of series of two, three or four notes and Part 2 is a train of individuals notes.We analyzed the development of S-type vocalizations of one female and one male litter of Ctenomys sp. from La Rioja, Argentina. Litters were captured in the field and sound recorded in our laboratory during the next 5 months beginning one week after capture.We recorded 65 vocalizations from the male (initial/final weight 70/135g) and 15 vocalizations from the female (initial/final weight 30/120g). Peak frequency values decreased in both individuals through time approaching the adult values: in the male from 222±28.8 Hz [range 183-269] to 175±31.5 Hz [129-247] (n=3 in each case), and in the female from 519±209 Hz [323-904] to 318±5.6 Hz [312-323] (n=3 in each case). Peak frequency in adult males (weight 240 g) is 181±8.4 Hz [161-193] (n=3), while we lack certain data on female vocalizations (weight 160 g).Litters gave only Part 1 which also had fewer series than in adults (maximum number of registered series were 6 in litter female, 17 in litter male and 98 adult males) and with longer silences between successive series than in adults (in litter male silences between series durations was 7.4±6.2 sec [1.9-27.5], in litter female 4.4±0.2 sec [1.6-11.4] in while in adults male was 0.7±0.1 sec [0.4-1.1]. This study is the beginning to understand the S-type vocalizations developed in this specie and allowed to observe how the peak frequency values of these two litters change during part of the period of growth.