image

Giant otter (Pteronura brasiliensis) swimming. This is the largest of the mustelids, with adult males reaching up to 1.8 metres in length and weighing up to 35 kilograms. Females are smaller and slimmer, reaching 1.7 metres and 26 kilograms. It inhabits wetlands in South America east of the Andes, where it feeds on fish, crabs and snakes. Adults have been known to kill and eat caimans. It is primarily a visual hunter, and catches its prey in underwater chases. It lives in groups of up to 20 individuals. Photographed in the Brazilian Pantanal. (KEYSTONE/SCIENCE PHOTO LIBRARY/MANUEL PRESTI)