Ultrasonic Vocalization Of Marmosets Case Study

Marmosets are exclusively arboreal, and one would assume that auditory signals are a particular important tool for communication, owing to the low visibility in trees. Within a repertoire of vocalizations, individual calls are often associated with specific behaviours. Information about the age, sex, group identity, motivational state, body size, affective state and reproductive status of a vocalizing individual, and clear considerations of the behavioral and environmental context of the vocalization, are prerequisites to ascertain its function. This requires the specification of the physical properties of the signal, a detailed knowledge of the situations, which evoke vocalizations and of the responses auditory signals in the receiving animals.
Mostly due to the fact that recordings made with semi-professional tape recorders give no information on the occurrence of ultrasonic frequencies. In addition, quality of recordings could be diminished by the presence of resonance and background noise. The living arrangements of the animals also made it difficult to identify the caller and to determine the social significance of the vocalizations. The recorder used by Bakker et al (2013) had an upper limit of 100kHz but even that seems not high enough to record all calls complete as his recordings showed that the observed loud shrills probably even went further above 100 kHz. This high frequency is even higher then Philippine tarsier (Tarsius syrichtaa) of which a vocalization with a dominant frequency of 70 kHz was recorded and assumed to be is among the highest recorded for any terrestrial mammal (Ramsier et al., 2012). For Philippine tarsiers, it was suggested that ultrasonic vocalizations might represent a private channel of communication that subverts detection by predators, prey and competitors, enhances energetic efficiency, or improves detection against low-frequency background
European Directive 2010/63/EU). Successful implementation of effective pain management strategies in animals requires objective and accurate assessment of discomfort, pain and distress and its severity in order to optimize welfare conditions. Traditional methods of welfare assessment based on monitoring of behaviour and clinical parameters have limitations such as the signs observed may not be specific to pain e.g. weight loss. One of the possibilities for assessing the well-being of marmosets might be, as is done with rodents (Burman et al., 2007; Kikusui et al., 2003), evaluating their production of ultrasonic vocalizations (USVs). Bakket et al., 2013 showed that marmosets produce USVs as part of their normal vocal repertoire, both in undisturbed conditions and in those that elicit changes in their emotional states. However, they conclude that USV production couldn’t be used as a reliable indicator of pain, discomfort or distress in