What is the largest dolphin?

The killer whale (Orcinus orca). Male killer whales can grow up to 9.6 m (31.5 ft). Spotted dolphins get to be about the size of a grown human-between 4-6 feet, up to 250 pounds.  When they are born, they are much smaller-usually between 2-2.5 feet.  Bottlenose dolphins grow to be between 6-8 feet.