Header

UZH-Logo

Maintenance Infos

The loud scratch: a newly identified gesture of Sumatran orangutan mothers in the wild


Fröhlich, Marlen; Lee, Kevin; Mitra Setia, Tatang; Schuppli, Caroline; van Schaik, Carel P (2019). The loud scratch: a newly identified gesture of Sumatran orangutan mothers in the wild. Biology Letters, 15(7):20190209.

Abstract

The communicative function of primates' self-directed behaviours like scratching has gained increasing attention in recent years, but their intentional use is still debated. Here, we addressed this issue by exploring the communicative function of ‘loud scratches’ in wild Sumatran orangutans. Building on previous studies in chimpanzees, we examined the prediction that audio-visual loud scratches are used communicatively in mother–infant travel coordination. Specifically, we examined whether individual, social and scratch features affected the use of pre-move scratches, markers of intentional signal use and approach responses. We analysed a total of 1457 scratching bouts, produced by 17 individuals (including four mothers and their dependent offspring) observed during 305 h of focal follows. Overall, we found that scratching bouts preceded departure mainly when these were produced by mothers and showed features of exaggeration. If the scratching individual was a mother, associates were more likely to be visually attentive during pre-move scratches than in other contexts. Approach or follow responses to scratches by individuals in association were predicted by context, the relationship with the scratcher (i.e. offspring) and the associate's attentional state. We conclude that orangutan mothers use loud scratches as communicative strategies to coordinate joint travel with their infants.

Abstract

The communicative function of primates' self-directed behaviours like scratching has gained increasing attention in recent years, but their intentional use is still debated. Here, we addressed this issue by exploring the communicative function of ‘loud scratches’ in wild Sumatran orangutans. Building on previous studies in chimpanzees, we examined the prediction that audio-visual loud scratches are used communicatively in mother–infant travel coordination. Specifically, we examined whether individual, social and scratch features affected the use of pre-move scratches, markers of intentional signal use and approach responses. We analysed a total of 1457 scratching bouts, produced by 17 individuals (including four mothers and their dependent offspring) observed during 305 h of focal follows. Overall, we found that scratching bouts preceded departure mainly when these were produced by mothers and showed features of exaggeration. If the scratching individual was a mother, associates were more likely to be visually attentive during pre-move scratches than in other contexts. Approach or follow responses to scratches by individuals in association were predicted by context, the relationship with the scratcher (i.e. offspring) and the associate's attentional state. We conclude that orangutan mothers use loud scratches as communicative strategies to coordinate joint travel with their infants.

Statistics

Citations

Altmetrics

Downloads

0 downloads since deposited on 08 Aug 2019
0 downloads since 12 months

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Anthropology
Dewey Decimal Classification:300 Social sciences, sociology & anthropology
Uncontrolled Keywords:Agricultural and Biological Sciences (miscellaneous), General Agricultural and Biological Sciences
Language:English
Date:26 July 2019
Deposited On:08 Aug 2019 09:35
Last Modified:08 Aug 2019 09:35
Publisher:Royal Society Publishing
ISSN:1744-9561
OA Status:Closed
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1098/rsbl.2019.0209
PubMed ID:31311488
Project Information:
  • : FunderFP7
  • : Grant ID201600
  • : Project TitleMEMSTICK - Synaptic mechanisms of memory loss: novel cell adhesion molecules as therapeutic targets

Download