Wilson, Rory P.Rose, Kayleigh A.Gunner, RichardHolton, Mark D.Marks, Nikki J.Bennett, Nigel CharlesBell, Stephen H.Twining, Joshua P.Hesketh, JamieDuarte, Carlos M.Bezodis, NeilJezek, MilosPainter, MichaelSilovsky, VaclavCrofoot, Margaret C.Harel, RoiArnould, John P.Y.Allan, Blake M.Whisson, Desley A.Alagaili, AbdulazizScantlebury, D. Michael2022-11-292022-11-292021-10Wilson, R.P., Rose, K.A., Gunner, R. et al. 2021, 'Animal lifestyle affects acceptable mass limits for attached tags', Proceedings of the Royal Society B-Biological Sciences, vol. 288, art. 20212005, pp. 1-9, doi : 10.1098/rspb.2021.2005.0962-8452 (print)1471-2954 (online)10.1098/rspb.2021.2005https://repository.up.ac.za/handle/2263/88535DATA ACCESSIBILITY : Data pertaining to this study are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.rjdfn2zbm [51).ELECTRONIC SUPPLEMENTARY MATERIAL is available online at https://doi.org/10.6084/m9.figshare.c.5672341.Animal-attached devices have transformed our understanding of vertebrate ecology. To minimize any associated harm, researchers have long advocated that tag masses should not exceed 3% of carrier body mass. However, this ignores tag forces resulting from animal movement. Using data from collar-attached accelerometers on 10 diverse free-ranging terrestrial species from koalas to cheetahs, we detail a tag-based acceleration method to clarify acceptable tag mass limits. We quantify animal athleticism in terms of fractions of animal movement time devoted to different collar-recorded accelerations and convert those accelerations to forces (acceleration × tag mass) to allow derivation of any defined force limits for specified fractions of any animal's active time. Specifying that tags should exert forces that are less than 3% of the gravitational force exerted on the animal's body for 95% of the time led to corrected tag masses that should constitute between 1.6% and 2.98% of carrier mass, depending on athleticism. Strikingly, in four carnivore species encompassing two orders of magnitude in mass (ca 2–200 kg), forces exerted by ‘3%' tags were equivalent to 4–19% of carrier body mass during moving, with a maximum of 54% in a hunting cheetah. This fundamentally changes how acceptable tag mass limits should be determined by ethics bodies, irrespective of the force and time limits specified.en© 2021 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License.Collar designDetrimentEthicsGuidelinesTag massArticle