Call Patterns and Basilar Papilla Tuning in Cricket Frogs. I. Differences among Populations and between Sexes

Male cricket frogs (Acris crepitans) produce a broad-band, high frequency advertisement call with a single spectral peak (the dominant frequency). We measured the dominant frequencies of male calls from six populations in central Texas and one from Indiana and compared them to the tuning of basilar papilla afferents in males and females. Averaging over all […]

Noise-dependent vocal plasticity in domestic fowl

Since acoustic communication is considerably constrained by environmental noise, some animals have evolved adaptations to counteract its masking effects. Humans and New World monkeys increase the duration of brief vocalizations (below a few hundred milliseconds) as the background noise level rises, a behaviour that increases the detection probability of signals in noise by temporal summation. […]

Auditory Perception of Conspecific and Heterospecific Vocalizations in Birds: Evidence for Special Processes

Budgerigars (Melopsittacus undulatus), canaries (Serinus canaria), and zebra finches (Poephila guttata castanotis) were tested for their ability to discriminate among distance calls of each species. For comparison, starlings (Sturnus vulgaris) were tested on the same sounds. Response latencies to detect a change in a repeating background of sound were taken as a measure of the […]

Spectral preferences and the role of spatial coherence in simultaneous integration in gray treefrogs (Hyla chrysoscelis)

The perceptual analysis of acoustic scenes may often require the integration of simultaneous sounds arising from a single source. Few studies have investigated the cues that promote simultaneous integration in the context of acoustic communication in nonhuman animals. This study of Cope’s gray treefrog (Hyla chrysoscelis) examined female preferences based on spectral features of conspecific […]

The cocktail party problem: What is it? How can it be solved? And why should animal behaviorists study it?

Animals often use acoustic signals to communicate in groups or social aggregations in which multiple individuals signal within a receiver’s hearing range. Consequently, receivers face challenges related to acoustic interference and auditory masking that are not unlike the human cocktail party problem, which refers to the problem of perceiving speech in noisy social settings. Understanding […]

Great tits in urban noise benefit from high frequencies in song detection and discrimination

Field studies in urban environments have shown that birds sing with higher frequencies in response to noise, but so far there are no perceptual data showing benefits of high-frequency songs over lowfrequency songs under typical urban noise conditions. In this study we investigated the potential effects of specific frequency use in different environments on the […]

Dip listening and the cocktail party problem in grey treefrogs: signal recognition in temporally fluctuating noise

Dip listening refers to our ability to catch brief ‘acoustic glimpses’ of speech and other sounds when fluctuating background noise levels momentarily decrease. Exploiting dips in natural fluctuations of noise contributes to our ability to overcome the ‘cocktail party problem’ of understanding speech in multitalker social environments. We presently know little about how nonhuman animals […]

Behavioural and physiological responses of domestic dogs (Canis familiaris) to agonistic growls from conspecifics

Motivation–structural rule theory predicts that a sender producing harsh, low frequency sounds directed at a conspecific modifies the receiver’s behaviour, in part, by communicating its willingness to escalate to an attack. Motivation–structural (MS) rules generally assume that receivers respond to this signal by retreating because of the threat encoded in the acoustic characteristics of the […]

Emotions in goats: mapping physiological, behavioural and vocal profiles

Emotions are important because they enable the selection of appropriate behavioural decisions in response to external or internal events. Techniques for understanding and assessing animal emotions, and particularly positive ones, are lacking. Emotions can be characterized by two dimensions: their arousal (bodily excitation) and their valence (negative or positive). Both dimensions can affect emotions in […]

Polar bear mother-offspring interactions in maternity dens in captivity

Two female polar bears at Dierenrijk Zoo in the Netherlands were monitored at their maternity den one day before the birth of their cubs and three days postpartum. Each bear was monitored for 96 hr to document behaviour and vocalisations. The goal was to obtain insight into the differences between the mother that lost her litter […]