River dolphins are cetaceans, which means that they related to whales and porpoises. These mammals live only in rivers and waterways of Asia and South America. There are five species of river dolphins belonging to three different families. In Asia the Baiji or Chinese river dolphin (Lipotes vexillifer) lives in the lower part of China's Chang Jiang or Yangtze River. On the Indian subcontinent, Indus river dolphins (Platanista indi) originally were found throughout almost the entire length of the Indus River, but now are limited to a stretch of that river in the Sind Province of Pakistan. Ganges river dolphins (Platanista gangetica) are found throughout the Ganges River, although their numbers are decreasing. In South America the Amazon river dolphin (Inia geoffrensis), also called the boto, is found primarily in the Amazon and Orinoco Rivers of Brazil and Venezuela. The South American franciscana river dolphin (Pontoporia...