The rare Southern River otter lives in freshwater systems with abundant riparian vegetation. It hunts mainly fish, but also forages for crabs, molluscs and birds.

It is found in inland lakes and close to the rocky coastal habitats of Argentina and Chile, never far from a source of freshwater.

The Southern River otter’s habitat is very fragmented, possibly due to its rarity and also the fact that this extremely shy animal avoids the many fishing villages and areas with no potential shelter. Imported salmon is taking over some areas, and by devouring local fish species and being too fast for otters to catch, its presence is proving to be a problem for the Southern River otter. In addition to this, trapping for otter pelts and conflict with fishermen is still very common in some areas.

The Southern River otter has been wiped out of much of its Argentinian areal because of habitat loss and poaching.