Piranha! For most people, the name sparks horror-movie images of vicious schools of fish that can reduce a human to a skeleton in minutes.
But do they really deserve this fearsome reputation? Piranhas are freshwater fish that are found in rivers and floodplains of South America. The most well-known species is the red-bellied piranha, but there are nearly forty other different species of piranha.
然而它们真的配得上这样恐怖的名声吗?食人鱼是一种淡水鱼类,多发现于河流及南美涝原上。最出名的种群莫过于红肚水虎鱼,不过水虎鱼的种类其实有大约四十种。
They aren't very large, but do have a mouth full of razor-sharp teeth and a strong jaw. So it may surprise you to learn that piranhas are not the bloodthirsty killers portrayed in films. They aren't even strict carnivores!
Most piranha species are omnivores and scavengers. Their diet is mostly made of insects and other fish, but also plants. During the rainy season when food is plentiful, piranhas eat more plants and insects. But in the dry season when ponds and rivers dry up and food becomes more scarce, piranha turn to meat-eating, usually in the form of other fish. Piranhas occasionally bite humans or other mammals when very hungry or threatened, but serious attacks are extremely rare.
大多种类的食人鱼是杂食动物、食腐动物。它们多以昆虫以及其它鱼类为食,但也吃植物。在雨季食物丰富时,食人鱼多数吃植物和昆虫。遇上旱季河流和湖泊干涸时,食物变得匮乏,食人鱼就开始吃肉,基本上是吃其他鱼类。但在饥饿或者受到威胁时,食人鱼偶尔会攻击人类或其他哺乳动物,但很少出现严重袭击事件。
Another common belief is that piranha form large schools for hunting, allowing them to attack larger prey than a single fish could. However, researchers found that piranha most likely group together as a defense against such predators as river dolphins, caimans and bigger fish, and not to engage in feeding-frenzies.
So while piranha may not win your hearts with cuddly good looks, they are probably more victim than vicious.