Not only these nasty little fish are vicious, but scientists have discovered that those bloody piranhas can talk to each other. They use three sounds, each of them meaning a different thing.

One of the sounds is a bark used to intimidate rivals. The other two are drumming songs produced when they attack each other for food. The finding is part of a larger study to learn the behavior of fish according to the sounds they produce, said the scientist leading the research, Eric Parmentier:

Eventually, if we understand the behaviour that's associated with the sounds, we might be able to listen to the sea and explain to fishermen: 'Now's not the best time to start fishing'.

They produce these sounds vibrating their swim bladders 150 times every second. If there's something that I hate more than piranhas is bickering piranhas. [The Journal of Experimental Biology via BBC]