Abstract # 117:

Scheduled for Saturday, August 26, 2017 04:00 PM-04:15 PM: (National Ballroom Salon A) Oral Presentation


M. M. Mulholland1,2 and N. G. Caine2
1University of Nebraska-Lincoln, Department of Psychology, Lincoln, NE 68588-0308, USA, 2California State University San Marcos

At least four New World primate species have individually distinct long calls, but this distinctiveness is not necessarily stable over time. Individually distinct mobbing calls have been demonstrated for three marmoset species but there has been no assessment of the stability of these differences. We recorded the tsik calls of six captive adult marmosets (Callithrix jacchus) in response to snake models at two time points six months apart. We measured eight acoustic variables including duration, inter-call interval, number of harmonics, minimum and maximum frequency, and starting, maximum, and ending peak frequency. Discriminant function analyses confirmed that calls recorded at the first time period (summer 2014) were individually distinct [82.48% correctly classified, X2(40)=2362.05, p<.001]. Stability of the calls was assessed using the DFA model for summer 2014 to classify calls elicited in winter 2015. The classification rates were lower, although still more than would be expected by chance [62%, X2(25)= 954.60, p<.05]. However, all six marmosets showed significant changes in at least four (out of eight) acoustic parameters during that six month period, and all eight parameters changed in two marmosets. In such a short time period, these changes in the acoustic structure of the tsik calls are unlikely due to changes in vocal tract morphology or other physical features of the marmosets, but instead may be linked to social changes within the groups.