Empathy  lets us feel another person's pain and drives us to help. Do any other animals feel empathy? Scientists recently found that rats  do, too. Most people don't like rats. In many people's eyes, rats are only bad. But Jean Decety and his partners at the University of Chicago did an experiment. It showed that rats are kind, warm-hearted animals. They can feel each other's pain. Scientists placed pairs of rats in plastic cages  for two weeks. During this time they got to know each other. Then they put one of the rats from each pair into a small container  in the cages. The small container had a door. It was so designed as to fall to the side when the free rat touched it. Many of the trapped  rats squeaked  to show their discomfort. The other rats of the pairs could see their suffering  friends clearly. In most pairs, the free rats would become very worried about their friends. They kept trying to save their friends again and again throughout the month. Scientists put the rats' favorite chocolate in the cages, but the rats didn't eat it until they had saved their friends successfully. Scientists also found that female rats seemed to act more empathetic than male rats. "The results are the first to show that rats take action in response to another's trouble," Decety said. "Monkeys and chimpanzees have similar behavior. But unlike those animals, rats can be ready used in laboratory studies. They will help us to learn which parts of the brain lead to empathy and helping behavior and whether empathy is natural." What does the passage mainly tell us?
Rats can feel other animals' pain. Chocolate is rats' favorite food. Rats are empathetic and can feel each other's pain. Female rats are more empathetic than male rats.