Abstract
Animal social systems are inherently dynamic, with individuals moderating how they associate with conspecifics according to spatiotemporal shifts in population demography and resource availability. Understanding such variation is important not only to further our knowledge of a species' ecology but also to gain insights into the factors influencing the evolution of animal social systems. Using a 10-year acoustic telemetry data set containing the movements and co-occurrences of 166 tagged individuals, we investigated how time of year, individual sex and maturity status affect the social organization and connectivity of a wild population of estuarine crocodiles, Crocodylus porosus. We found that our tagged population of crocodiles displayed social structure, where individuals segregated spatially into distinct communities along 120 km of river and estuary. The social organization and structure of these communities were temporally dynamic, with association rates and the connectedness of individuals peaking during the dry season before disintegrating prior to the onset of the wet season. The formation of communities was found to coincide with an increase in the frequency of co-occurrence events between mature and mature–immature dyads prior to the onset of the mating season. Together these findings indicate that estuarine crocodiles have a structured social system, where the proximity to the mating season and an individual's maturity status dictate how they associate with conspecifics.
| Original language | English |
|---|---|
| Pages (from-to) | 59-78 |
| Number of pages | 20 |
| Journal | Animal Behaviour |
| Volume | 199 |
| DOIs | |
| Publication status | Published - May 2023 |
Bibliographical note
Funding Information:We acknowledge the Taepadhigi, Tjumgundji and Warranggu peoples as the traditional owners on whose land we conducted our research and recognize their continued and ongoing connection to country. We thank Australia Zoo staff for their aid in the capture and tagging of estuarine crocodiles. Acoustic hydrophone data from the Port Musgrave region were provided by Rio Tinto Aluminium Limited. This study was supported by the Australian Research Council linkage scheme with Australia Zoo and CSIRO as industry partners (grant number LP140100222 ). Donations towards research and field costs were also received from the Australia Zoo Wildlife Warriors foundation ( https://wildlifewarriors.org.au/conservation-projects/crocodile-research ). C.J.B. was supported by an Australian Government Research Training Program Scholarship.
Funding Information:
Data were sourced from the Acoustic Animal Tracking Database ( https://animaltracking.aodn.org.au ) of the Integrated Marine Observing System (IMOS, www.imos.org.au ). IMOS is a national collaborative research infrastructure supported by the Australian Government. The database is a centralized acoustic telemetry data repository maintained by the IMOS Animal Tracking Facility and the Australian Ocean Data Network (AODN, https://portal.aodn.org.au/ ). The processed data and all R code supporting the analyses reported in this article are available from GitHub: ( https://github.com/Cameron-J-Baker/Baker_et_al_2023_Ani_Behav ).
Funding Information:
We acknowledge the Taepadhigi, Tjumgundji and Warranggu peoples as the traditional owners on whose land we conducted our research and recognize their continued and ongoing connection to country. We thank Australia Zoo staff for their aid in the capture and tagging of estuarine crocodiles. Acoustic hydrophone data from the Port Musgrave region were provided by Rio Tinto Aluminium Limited. This study was supported by the Australian Research Council linkage scheme with Australia Zoo and CSIRO as industry partners (grant number LP140100222). Donations towards research and field costs were also received from the Australia Zoo Wildlife Warriors foundation (https://wildlifewarriors.org.au/conservation-projects/crocodile-research). C.J.B. was supported by an Australian Government Research Training Program Scholarship.
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© 2023 The Authors