Dolphins are small whales, and dolphins are very ancient creatures. According to fossil evidence,
scientists say the modern dolphins first appeared on earth during the Miocene period, 25 million
years ago. Rare dolphin species live in rivers in the Amazon and China, but most dolphins live in the
temperate oceans . There are 26 recognized species of Delphinidae (dolphin), and dolphins are the
most diverse family of the Cetaceans. Cetaceans comprise all whales, porpoises, and dolphins