Giant Brasilian Otter : Diet
A vicious diet
Giant Otters prefer fish such as perch and catfish, which they typically eat head-first. The exception to this is the piranha. These voracious fish won't attack otters in the water because the otters are much to swift and big, but the otters make sure to eat them tail first, so they're definitely dead by the time they get to the razor-sharp teeth! An otter can get through as much as 10kg of fish in one day. This unfortunately leads to competition with local tribes of indians over fish stocks.
As well as fish, they will eat crustaceans, baby caiman (the South American version of the crocodile) and snakes - even anacondas, though maybe not the 20 foot long monsters.
Giant Otters are diurnal and prefer to hunt by sight. However, like most otters, their whiskers can be used in muddy water to detect the movement of prey. When they hunt in groups the otters will hunt in midstream, but when alone they tend to stick to the shallower waters. They have two swimming speeds - to swim slowly they paddle with all four paws, but to put on a burst of speed they tuck their paws in and undulate their large flattened tails. On land they are much less agile and it is only here that they may find themselves hunted! Jaguars will occasionally take giant otters - humans are a much greater danger to them.
Without current human pressures, Giant Otters would have little trouble finding enough to eat. The rivers of the rainforest are teeming with fish and especially so during the dry season. During this half of the year the lakes dry up to a few inches of water and fish are concentrated in huge numbers, easy prey for otters. During the wet season the forests flood and the otters follow the spawning fish amongst the trees.