When you think of piranhas, you probably think about a fierce fish with
razor sharp teeth. You might even think of a river that looks like its boiling with
swarms of hungry fish, eating an animal all the way down to its bone in just a few
minutes. I dont think you would want to get close to a piranha. But in reality, if
you did, the piranha would look at you and decide that you werent really good to
eat and just leave you alone and swim away.
Even the scientists who study piranhas dont agree with each other on
how dangerous piranhas are to people. There is no proof that a piranha has ever
killed a person. Most piranha bites happen when fishermen try to take the
piranha off the hook and piranha bites them. A lot of fishermen have lost fingers
and toes to piranhas this way.
Piranhas live in most of South America and nowhere else in the world.
The piranhas range from southern Venezuela to the northern part of Argentina.
They are found in all of the major rivers in South America that flow into the
Atlantic Ocean, including the Amazon, Orinoco, Esscquibo, La Plata, and Sao
Francisco. They are lowland fish that live in big rivers and small streams. They
also inhabit lagoon, ponds, lakes, and reservoirs. They live in fresh waters in
tropical forests and tropical savannas, or grasslands. Piranhas dont live in
mountain streams or mountain lakes, probably because the water is way too cold
and also because the water flows too fast that they cant catch the fish living in it.
The piranhas ancestors first showed up 100 million years ago. They
showed up in a fresh water lake on a continent that is now South America. They
had one feature that made them different from the earlier fish before them and
thats a chain of small bones called Websters Ossicles. These are the first four
vertebrae of the backbone. This allowed the fish to hear better, especially high
pitched sounds. Fish that have Websters Ossicles are classified as
Ostariophysans. The Ostariophysans evolved into many different groups of fresh
water fish. One of the first was the piranha, so they were on e of the first to have
good hearing. They could find food easier and can escape predators better by
using their hearing. There are over 30 different species of Piranhas today.