P. Hansen

Bio: P. Hansen is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 7 citations.

RECENT BIOACOUSTIC PUBLICATIONS (2008 and earlier)

Abstract: (2009). RECENT BIOACOUSTIC PUBLICATIONS (2008 and earlier) Bioacoustics: Vol. 18, No. 3, pp. 291-318.

Human cerebral response to animal affective vocalizations

Abstract: It is presently unknown whether our response to affective vocalizations is specific to those generated by humans or more universal, triggered by emotionally matched vocalizations generated by other species. Here, we used functional magnetic resonance imaging in normal participants to measure cerebral activity during auditory stimulation with affectively valenced animal vocalizations, some familiar (cats) and others not (rhesus monkeys). Positively versus negatively valenced vocalizations...

Chimpanzees modify recruitment screams as a function of audience compositiond with a question mark

Abstract: Wild chimpanzees produce acoustically distinct scream vocalizations depending on their social role during agonistic interactions with other group members. Here, we show that victims during such agonistic interactions alter the acoustic structure of their screams depending on the severity of aggression experienced, providing nearby listeners with important cues about the nature of the attack. However, we also found that victims of severe attacks produced screams that significantly exaggerated the true level of aggression experienced, but they did so only if there was at least one listener in the audience who matched or surpassed the aggressor in rank. Our results are consistent with the more general hypothesis that chimpanzees possess sophisticated understanding of third-party relationships, so-called triadic awareness, and that this knowledge influences their vocal production.

Do Dolphins Eavesdrop on the Echolocation Signals of Conspecifics? - eScholarship

Abstract: Preliminary experimental evidence shows that it is possible for an eavesdropping dolphin to discern object information from the returning echoes generated by the echolocation signals of conspecifics. Researchers have offered suggestions as to how this proposed ability may affect the behavior of wild dolphin species. A review of early and contemporary ideas, hypotheses and experiments concerning eavesdropping in dolphins is presented here, resulting in the development of a formalized, modern version of the ‘echoic eavesdropping’ hypothesis. The ecological implications of eavesdropping behavior remain unknown; refinement of the hypothesis and clarification of underlying assumptions are vital to our understanding of how echoic eavesdropping behavior might manifest itself in the social behavior of wild odontocetes. Suggestions for future research involving both echoic eavesdropping and a novel, alternative hypothesis (multi-source echoic eavesdropping) are offered. With the potential to elucidate many of the mysteries concerning dolphin biosonar use and dolphin behavior in general, echoic eavesdropping is an idea that deserves future attention.

Echolocation calls of rhinolophid and hipposiderid bats in Swaziland : research article

Abstract: Echolocation call parameters of six species of rhinolophid and hipposiderid bat species occurring in Swaziland are presented. All calls were obtained with the frequency-division ANABAT bat detector, and mostly from hand-held individuals. There did not appear to be any differences in calls between hand-held and free-flying bats. However, there were significant inter-specific differences with respect to the constant frequency component of the call (equivalent to maximum frequency) and call duration. Minimum frequency was found to be highly variable, and considered not useful for species identification of free-flying individuals. Call parameters obtained in this study are very similar to those obtained with the time-expansion Pettersson detector, suggesting that for this group, choice of detector makes little difference. It is suggested that bat detectors provide an important method to inventory southern African bats, and supplement traditional, capture-based techniques, notably mist nets and harp traps.

Calls of the Wild

Abstract: The article discusses the effect of human development on bioacoustics. The replacement of natural bird, animal, and insect sounds with the sounds of human civilization is discussed. Bioacoustics expert Bernie Krause describes the potential effect of noise pollution, saying that it can disrupt animals' mating calls, discourage animals from grazing, and prevent animals from hearing nearby predators.