The beluga whale (Delphinapterus leucas) is an Arctic and sub-Arctic cetacean. Arctic characteristics differentiate it from other cetaceans, including the white color and absence of a dorsal fin. Their body size is between that of a dolphin and a true whale. During summer they can gather by the hundreds in estuaries and shallow coastal areas. This photo was taken in July on the Churchill River in Canada. The belugas seemed happy to see us and rushed over to swim alongside our inflatable boat.