1. piranha
   shark
2. whale

Theodore Roosevelt took a special interest in piranha fish. He wrote about piranha in his book, "Through the Brazilian Wilderness."

1. on purpose
   by accident
2. neither answer

The piranhas are released into the river by accident.

1. maximum size is two feet
   most are about eight inches
2. both answers

The maximum size of a piranha may be about two feet (60 cm), but most are about eight inches (20 cm) long.

1. Serrasalmus rhombeus
   Pigocentrus naterreri
2. Pristobrycon striolatus

The Pigocentrus naterreri is the most vicious of the species.

1. razors
   brushes
2. sandpaper

Piranha have teeth like razors.

1. chomping
   biting
2. nibbling

The piranha jaw is designed for chomping.

1. overlapping pattern
   interlocking pattern
2. tight vertical pattern

The teeth are spaced in an interlocking pattern, the better to chomp with.

1. chew
   chomp
2. devour

The piranha do not chew their prey, they chomp it.

1. no chewing
   flesh goes to stomach
2. both answers

Piranha do not chew, so the big bite goes straight to its stomach.

1. change positions very fast
   movement of the prey
2. neither answer

Piranhas let everyone in the school get a big bite, so when they change positions, very fast, the water bubbles with their movement.

1. herons
   caimans
2. both answers

Piranhas are the prey of herons and caimans.

1. dead animals
   live animals
2. fruit

Mainly piranhas are scavengers, so they eat dead animals.

1. no availability
   endangered species
2. illegal to import

Piranha are illegal to import, so don't plan on keeping one in your home aquarium.

1. fish
   fruit
2. mammals

Piranhas eat fish, and occasionally will eat another piranha.

1. slowest-moving water
   fast-moving water
2. rapids

Piranhas prefer to breed in slow-moving water. An increase in dam building in South America has increased slow-moving waters and is thought to account for an increase in the piranha population.

1. pet piranhas have been dumped
   purposeful destruction of waterways
2. neither answer

Anywhere but South America would be an unlikely place to find piranhas. One explanation is that "pet" piranhas have been dumped into waterways, after the owners discovered just how difficult they were to keep.

1. threaten the ecological balance
   increase the fish population
2. increase tourism

The addition of piranhas to these waterways may threaten the ecological balance.

1. 10
   20
2. 30

About 20 piranha make up a typically sized school, but it takes hundreds to eat a cow.

1. strip a human
   strip a cow
2. strip a monkey

Roosevelt witnessed a school of piranhas strip a cow to the bone in a very short time, perhaps around one minute. It is thought that the piranhas he saw had been intentionally starved beforehand.

1. one-quarter inch
   one-half inch
2. one inch

The teeth are only about one-quarter inch (0.6 cm) long.