Memory-dependent adjustment of vocal response latencies in a territorial songbird.

Vocal interactions in songbirds can be used as a model system to investigate the interplay of intrinsic singing programmes (e.g. influences from vocal memories) and external variables (e.

Do Barbary macaques 'comment' on what they see? A first report on vocalizations accompanying interactions of third parties.

Primates acquire knowledge about relationships of third parties and group structure by monitoring their conspecifics. We show that Barbary macaques (Macaca sylvanus) utter specific vocalizations while monitoring interactions of other group members. As they did not direct other behaviours to the interacting group members, we provisionally termed these vocalizations 'vocal comments'.

Approaches to the mechanisms of song memorization and singing provide evidence for a procedural memory.

There is growing evidence that, during song learning, birds do not only acquire 'what to sing' (the inventory of behavior), but also 'how to sing' (the singing program), including order-features of song sequencing. Common Nightingales Luscinia megarhynchos acquire such serial information by segmenting long strings of heard songs into smaller subsets or packages, by a process reminiscent of the chunking of information as a coding mechanism in short term memory. Here we report three tutoring experiments on nightingales that examined whether such 'chunking' was susceptible to experimental cueing.

From birdsong to speech: a plea for comparative approaches.

Human language and speech are unique accomplishments. Nevertheless, they share a number of characteristics with other systems of communication, and investigators have thus compared them to birdsong and the vocal signaling of nonhuman primates. Particular interesting parallels concern the development of singing and speaking.

Acoustic communication in noise: regulation of call characteristics in a New World monkey.

This study on common marmosets Callithrix jacchus is the first to examine noise-dependent mechanisms of vocal plasticity in a New World monkey. Since acoustic communication can be considerably impaired by environmental noise, some animals have evolved adaptations to counteract its masking effects. The studied marmosets increased the sound level of their spontaneous calls in response to increased levels of white noise broadcast to them.

Can dolphins heal by ultrasound?

In recent years, dolphin-assisted therapy has become very popular and an increasing number of facilities offer therapy programs with dolphins worldwide. To this date, there are no studies concerning the behavior of dolphins during these therapies. As a result of speculations that the echolocation of dolphins may play an important role for the success of the therapy and the high publicity of this in the media, people pay much more for dolphin-assisted than for other animal-assisted therapy programs.

Dynamic-acoustic variation causes differences in evaluations of laughter.

Exposure to laughter has striking effects on human listeners and may facilitate positive emotional and behavioural responses. The acoustic signal pattern of laughter vocalisations is particularly suitable to elicit these reactions. However, little is known about factors that lead to differences in reactions of listeners.

The use of vocal signals in the social play of barbary macaques.

Field studies in various species of Macaca (Cercopithecidae) provided evidence for specific visual displays that typically accompany playful interactions. The aim of our study was to examine whether and when playing individuals would use auditory displays, i.e.

Dusk calling in barbary macaques (Macaca sylvanus): Demand for social shelter.

Barbary macaques (Macaca sylvanus) show an increase in vocal activity at dusk. This investigation showed that these vocalizations were mainly produced by juveniles from six to 18 months of age, during their attempts to achieve body contact with their mothers, thereby building up a sleeping cluster. The "dusk calling" consisted of protracted sequences of variable vocal patterns which always ceased when the juvenile joined its preferred sleeping cluster.

Communal roosting and formation of sleeping clusters in barbary macaques (Macaca sylvanus).

Sleeping cluster composition and distribution were studied in a semi-free-ranging population of 174 Barbary macaques (Macaca sylvanus) in Rocamadour/France. Over a period of 2 months 341 sleeping clusters comprising 754 animals were recorded as animals left the sleeping trees. To control for nocturnal activities five observation periods were conducted, each of which covered a complete night.