The Australian crocodile is the largest crocodile in the world. It can grow up to seven meters long, and the biggest can weigh up to 1,000 kilometers. It has only two muscles to open its mouth but 40 to close it! What makes crocodiles so dangerous is that they attack extremely quickly, and they take their victims under the water to drown them. They usually attack in the water, but they can suddenly come out of a river and attack animals or people. And they can run on land as fast as 17 kilometers per hour. Every year in Australia there are crocodile attacks on humans. Two years ago a 24-year-old German tourist died when she went for a swim in a lake. Although there were signs warning people that there might be crocodiles, the woman and her friends decided to go for a midnight swim. The woman suddenly disappeared, and the next morning her body was found. Near it was a four-meter long crocodile. And only last month two Australian boys watched in horror as their friend was killed by a crocodile when they were washing their bikes in a river. They climbed a tree and stayed there for 22 hours while the crocodile waited below. But you can survive a crocodile attack. Last year Norman Pascoe, a 19-year-old, was saved from a crocodile when his aunt hit it on the nose. Norman's aunt said: "I hit it and I shouted, 'Help!' The crocodile suddenly opened its mouth and my nephew escaped."