Baboon responses to graded bark variants

Citation
J. Fischer et al., Baboon responses to graded bark variants, ANIM BEHAV, 61, 2001, pp. 925-931
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences","Neurosciences & Behavoir
Journal title
ANIMAL BEHAVIOUR
ISSN journal
0003-3472 → ACNP
Volume
61
Year of publication
2001
Part
5
Pages
925 - 931
Database
ISI
SICI code
0003-3472(200105)61:<925:BRTGBV>2.0.ZU;2-G
Abstract
We studied chacma baboons', Papio cynocephalus ursinus, responses to conspe cific 'barks' in a free-ranging population in the Okavango Delta of Botswan a. These barks grade from tonal, harmonically rich calls to calls having a noisier, harsher structure. Tonal or clear barks are typically given when t he signaller is at risk of losing contact with the group or when a mother a nd infant have become separated ('contact barks'). The harsher variants are given in response to predators ('alarm barks'). In both contexts, however, we also observed acoustically intermediate forms. Using the habituation-re covery method we tested whether baboons discriminated between (1) clear con tact barks versus harsh alarm barks, and (2) clear contact barks versus int ermediate alarm barks. Calls were selected according to the results of a di scriminant function analysis conducted on a suite of acoustic parameters. I n these experiments, animals showed a significant recovery of response only after playback of the harsh alarm call. We performed another set of experi ments using single exemplars of clear and intermediate contact barks, or in termediate and harsh alarm barks. Animals responded only to the playback of a harsh alarm bark. Apparently, only this harsh variant was placed in a ca tegory that warranted a response. We hypothesize that baboons' responses we re to a large degree influenced by their assessment of context. (C) 2001 Th e Association for the Study Animal Behaviour.