Tsunamis are large, powerful waves caused by undersea earthquakes. In 2004, a tsunami hit parts of India and Thailand, killing over 150,000 people. However, many animals seemed to sense the impending disaster and fled to safety, including elephants that screamed and ran inland and zoo animals that rushed into shelters. Some experts believe animals have a sixth sense or can detect vibrations that humans cannot, allowing them to escape danger from natural disasters like tsunamis.