Header

UZH-Logo

Maintenance Infos

How to measure chimpanzee party size? A methodological comparison


van Leeuwen, Kelly L; Matsuzawa, Tetsuro; Sterck, Elisabeth H M; Koops, Kathelijne (2020). How to measure chimpanzee party size? A methodological comparison. Primates, 61(2):201-212.

Abstract

Chimpanzees (Pan troglodytes) live in fission–fusion societies where community members form temporary parties that frequently change in size and composition. Chimpanzee party size and composition have been widely studied to identify proximate causes of grouping patterns, and party size estimates are used to assess population sizes and densities. Numerous socio-ecological factors influence chimpanzee party size, but findings differ across studies. Various methods to measure party size exist, including direct observations, motion-triggered camera (MTC) observations, and nest counts. However, comparative analyses of these methods are lacking. Here, we assess relative differences in four commonly used party size methods and we examine socio-ecological factors influencing party size of unhabituated chimpanzees (P. t. verus) at Seringbara, Nimba, Guinea. We also assess which method(s) best reflect the influence of socio-ecological factors on party size. Using data collected over 69 months, we show that night nest counts resulted in relatively larger party size estimates than the other methods, and day nest counts resulted in relatively smaller party size estimates. Direct and MTC observations did not differ in relative estimates of party size and composition. Both fruit abundance and presence of estrous females positively influenced party size, but this effect was only evident when measuring party size with MTCs. Methods thus differ in relative party size estimates and their ability to assess the impact of socio-ecological factors. We conclude that MTC observations best represent party size and the effect of socio-ecological factors at Nimba. MTCs show promising potential for studying grouping patterns in unhabituated chimpanzees.

Abstract

Chimpanzees (Pan troglodytes) live in fission–fusion societies where community members form temporary parties that frequently change in size and composition. Chimpanzee party size and composition have been widely studied to identify proximate causes of grouping patterns, and party size estimates are used to assess population sizes and densities. Numerous socio-ecological factors influence chimpanzee party size, but findings differ across studies. Various methods to measure party size exist, including direct observations, motion-triggered camera (MTC) observations, and nest counts. However, comparative analyses of these methods are lacking. Here, we assess relative differences in four commonly used party size methods and we examine socio-ecological factors influencing party size of unhabituated chimpanzees (P. t. verus) at Seringbara, Nimba, Guinea. We also assess which method(s) best reflect the influence of socio-ecological factors on party size. Using data collected over 69 months, we show that night nest counts resulted in relatively larger party size estimates than the other methods, and day nest counts resulted in relatively smaller party size estimates. Direct and MTC observations did not differ in relative estimates of party size and composition. Both fruit abundance and presence of estrous females positively influenced party size, but this effect was only evident when measuring party size with MTCs. Methods thus differ in relative party size estimates and their ability to assess the impact of socio-ecological factors. We conclude that MTC observations best represent party size and the effect of socio-ecological factors at Nimba. MTCs show promising potential for studying grouping patterns in unhabituated chimpanzees.

Statistics

Citations

Dimensions.ai Metrics

Altmetrics

Downloads

4 downloads since deposited on 03 Feb 2021
4 downloads since 12 months
Detailed statistics

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
Scopus Subject Areas:Life Sciences > Animal Science and Zoology
Uncontrolled Keywords:Animal Science and Zoology
Language:English
Date:1 March 2020
Deposited On:03 Feb 2021 13:21
Last Modified:04 Feb 2021 21:00
Publisher:Springer
ISSN:0032-8332
Additional Information:This is a post-peer-review, pre-copyedit version of an article published in Primates. The final authenticated version is available online at: https://doi.org/10.1007/s10329-019-00783-4
OA Status:Green
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1007/s10329-019-00783-4
PubMed ID:31894437

Download

Green Open Access

Download PDF  'How to measure chimpanzee party size? A methodological comparison'.
Preview
Content: Accepted Version
Filetype: PDF
Size: 333kB