Intraspecific Agonism between Giant Otter Groups

In August 2002, we studied Giant Otters in the region of the Vermelho river, in the Brazilian Pantanal. During our research, we observed and filmed a particularly aggressive interaction between two groups of Giant Otters at the junctions of the rivers Vermelho and Miranda. This article reports the event and presents a sonogram of the very stereotypic vocalisations of the aggressor group.