Negative relationship between body mass and home range size in three-toed sloths of the Amazon rainforest

ABSTRACT

The spatial use of habitat is key to understanding the ecology of animals and their area requirements. In the current study, the locations of 11 wild pale-throated three-toed sloths (Bradypus tridactylus) were tracked using GPS loggers across 92 days in a 776 ha forest fragment in the central Amazon. Although male home ranges were slightly smaller than those of females, there were no significant differences in size or its expansion patterns. For nine of 11 individuals, home range size reached a plateau within 45 days of study start, indicating that 45 days can be the basal minimum days to establish the home range size of B. tridactylus. There was a negative relationship between body mass and home range size in our study. This counterintuitive result may be caused by disparities in the food-exploring abilities between individuals. Smaller and presumably younger individuals, who have less experience, may require more time and a larger area in which to search for food, while older and more experienced individuals may be able to find food efficiently in a smaller area. Further work on the distribution of food plants and the food-exploring pattern of each animal in relation to age and/or size is thus encouraged.

KEYWORDS:

• Bio-logging
• GPS
• body size effect
• Bradypus tridactylus
• movement ecology
• home range

Acknowledgments

The authors would like to thank Edson Rodrigues Costa, Leandro Siqueira Fernandes, Raiclicia Batista, and Projeto Sauim-de-Coleira staff for their assistance in our field and laboratory work, the security staff of Federal University of Amazonas for providing information on visual encounters with wild sloths, and Dr Hirofumi Hirakawa at the Forestry and Forest Products Research Institute, Hokkaido, Japan, for providing a custom-made software KMLFiler ver.3–10. We also thank Prof. Shiro Kohshima at Kyoto University for his continuous support of our study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

LVV found the phenomenon and designed this study with DM. DM, AS, TY, and MG conceived of the project. LVV, DM, and AS conducted fieldwork and collected data. DM and LVV analyzed data and wrote the manuscript, and MG, TY, and AS revised it.

Ethical standards

All the research procedures were approved by the biodiversity authorization and information system (SISBIO − 60116-1) and the Ethics Committee of the Federal University of Amazonas (006/2018-CEUA/UFAM).

Data availability statement

The relocation data are available at Mendeley Data: https://dx.doi.org/10.17632/4pw5hp9r7w.1.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/01650521.2024.2375932.

Additional information

Funding

This work was supported by JST/JICA, SATREPS under Grant 1302260 and JSPS Core-to-Core Program, A. Advanced Research Networks, “International Core of Excellence for Tropical Biodiversity Conservation focusing on Large Animal Studies”.