Green sloths and brown cows: the role of dominant mammalian herbivores in carbon emissions for tropical agro‐ecosystems

When Neotropical forests are cleared, there is a rapid switch in the dominant herbivore from wild sloths (suborder Folivora) to domestic cows Bos taurus . We quantified carbon dynamics for these mammals and the ecosystems they inhabit. Because of their low metabolic rates and photosynthetically‐active algae, sloths emit trivial amounts of carbon (12 g C/sloth*day) compared to cows (2.3 kg C/cow*day). In parallel, forests are carbon sinks (−242 g C/m 2 *year) and pastures sources (261 g C/m 2 *year); cows contribute >50% of the net emissions from pastures. For a small farm in Costa Rica, this turnover in herbivores translates into ~166 metric tonnes of additional C emitted annually.