Habitat and feed
They live in the Amazon river system in South America where they usually live in shoals of around 30 individuals, but in extreme cases as many as 2000 individuals have been heard of. They usually feed on small fish, insects, as well as sick and dead fish/animals. It has never been proven that they have killed people, but examples have been heard of where they have eaten people. However, these people have drowned before the piranhas have started eating them.
Swimming with piranhas
So there is no need to fear to be eaten right down to the bones if you bathe in the Amazon river system – the locals do it all the time. However, piranhas have razor sharp teeth and very powerful jaw muscles. In general, they only attack if they are starving, are in an unnatural situation or feel threatened enough, but in those cases they can easily bite off a finger or a toe.
Big differences from one place to another
There is a big difference between the species and also between the single individuals. Some places you can see natives bathing in the river, but only a few miles upstream it would be far more risky. You must respect them, but ordinary interaction in their natural habitat should not give reason to be apprehensive. The big difference in the behaviour of the piranhas from one place to another can be caused by a larger number of fish, lack of feed, damming or other things such as the waste from cleaning fish being thrown in the water where the blood attracts hungry fish.
Cannibalism among piranhas
Although piranhas live in shoals and thereby seek safety from larger fish, they can not feel completely safe in the shoal, because cannibalism is a natural thing among piranhas in times of food shortage. At such a time they even set their own young on the menu. Finally piranhas is nature’s own answer to our garbage collectors, they take anything left over that nobody else wants.
When are piranhas most dangerous?
Piranhas are most likely to live up to their name and reputation in times of drought where they may be trapped in lakes where the water slowly evaporates. They will then be pressed for space and lack of enough feed. In that case a shoal of hungry piranhas will attack larger animals.