A visitor recently left a comment asking:

WHAT ABOUT HOW GOOD ARE DOLPHINS AT SWIMMING?

From Dolphin facts Page 2,

During normal travel, if the distance to be travelled is under 2500 meters, a Dolphin can travel at 11-12.5 km/hr. Sometimes, when chasing boats, dolphins have been reported to travel at speeds of 26.7 km/hr. Otherwise, a dolphin will travel at speeds of between 6 and 8 km/hr, as their motion is most efficient at these speeds. At higher speeds, dolphins tend to jump clear out of the water. This actually helps the Dolphin save energy, as the air provides a lot less resistance than the water. It is estimated that dolphins can reach speed of up to 30 km/hr, but that is only in short burst as when preparing for a jump, or similar burst of energy.