National Geographic : 1940 Jan
THE NATIONAL GEOGRAPHIC MAGAZINE Photograph by \Villard K. Lulver AN EXUBERANT DOLPHIN SEEMS TO JUMP FOR JOY This Bottlenose is sporting near a ship off the Rhode Island shore. The animals may leap as much as twice their own length above the surface, and in captivity have been known to turn somersaults. This dolphin is one of the types frequently seen along the Atlantic coast (Plate XVII). French Guiana (Plate XXIII). About a dozen species of Sotalia inhabit the tropical coastal waters or rivers of South America, Africa, India, and the lands bordering the China Sea. Two of the three species native to the Amazon often are found in its smaller tribu taries, 1.500 or more miles upstream from the sea. When the German scientist, Alexander von Humboldt, was traveling by boat along the Rio Temi to Yavita on the Venezuela Colombia frontier, his Indian boatmen usually followed open leads through the inundated for est. In the thickest part of the forest where the depth of the water was not more than half a fathom, Humboldt was astonished to see a school of these fresh-water dolphins suddenly appear around his boat. The Guiana River Dolphin differs from others in having a slimmish body, a relatively large dorsal fin, and a peculiarly shaped slen der beak. It is usually about five feet long. The dull lead-colored or brownish upper parts blend on the lower third of the sides with the pinkish or violet-gray underparts. Narwhal (Monodon monoceros) Narwhals are inhabitants of Arctic seas and under favorable open-water conditions wander along the Arctic coasts of the Old and New Worlds (Plate XXIV). The male Narwhal differs from all other whales and porpoises in having the left upper jaw armed with a clockwise spirally twisted tusk, which occasionally measures more than nine feet (page 83). The Narwhal never has been known to use its tusk as a weapon. The tusks were first taken to Europe as articles of trade by Norsemen from Iceland and Greenland. Narwhals generally migrate in large herds. In the spring when the ice is rotten and cracked, they frequent the openings, apparently to escape being attacked by Killer Whales. The calves, which are gray, and five feet in length at birth, remain with the mother for a long time. The shrill whistle made by the Narwhal just as it bobs up out of the water may result from forcing the respiratory blast through the water. The deep roar or short low pitched blast sometimes heard may be made by the nostrils of a mother calling to her calf. Cuttlefish, skate, turbot, rock cod, salmon trout, sea scorpions, and shrimps have been found in Narwhal stomachs, and small halibut and flounders are among their favorite foods. Fish are crushed between the jaws and swal lowed without mastication, since there are no functional teeth.