Repeated measures ANOVA testing the effects of time (weeks 0–4) and group size on fecal glucocorticoid levels in <i>Atelopus</i> housed together (groups of 8 vs 2).

<p><i>(</i><b><i>a</i></b><i>). We omitted group size n = 1 from the analysis because there were too many missing values to run statistical comparisons. Repeated measures ANOVA testing the effects of time (weeks 1–4) and group size (8 vs 2) on aggressive interactions in Atelopus housed together (</i><b><i>b</i></b><i>).</i></p

Ethogram describing different types of aggressive interactions observed for <i>Atelopus</i>.

<p><b>Fight</b>: Combat involving mouth or front limbs, often flipping of opponent; <b>Mount</b>: >50% of initiators body covers the victim for >5 seconds; <b>Release call</b>: High pitched, weak, peep like call; maximum tally of one per individual; <b>Physical contact</b>: Any remaining forms of physical contact; <b>Stalk</b>: One individual actively follows/chases another for >5 seconds; <b>Wave</b>: Circular movements in front limbs.</p

Cortisol EIA profile (black, diamond marks) and Corticosterone RIA profile (grey, triangle marks), in <i>Atelopus</i> feces following an ACTH challenge (0.2 IU, IM).

<p>Cortisol EIA profile (black, diamond marks) and Corticosterone RIA profile (grey, triangle marks), in <i>Atelopus</i> feces following an ACTH challenge (0.2 IU, IM).</p

Fecal glucocorticoid concentrations immediately before and after male <i>Atelopus</i> were grouped together at week 1 (ng cortisol/g ± SEM) changed significantly over time (p = 0.04*), but there were no significant differences between groups sizes (A).

<p>Frogs housed singly (mean  = 44.2 ng cortisol/g±7.4 SEM) could not be included in this analysis because of too many missing values. Aggressive interactions changed significantly over time (p<0.001***), but there were no significant differences between group sizes.</p