La Plata dolphin

La Plata dolphin ( Pontoporia blainvillei )

The La Plata dolphin ( Pontoporia blainvillei ) is a common South American river dolphin. It is the smallest of all river dolphins and the only species that lives in the sea.

Features

With a size of 130 to 170 cm and a weight of 35 to 50 kg of this river dolphin is of graceful form. He has a gray-brown body color, which is brighter towards the belly. The head is small and set off by a slight nuchal fold from the fuselage. The eyes are small but well developed. The blowhole is crescent shaped. The muzzle is relative to the body the longest of all whales and very slim with a straight mouth line. In the upper jaw sit 106-116, in the mandible 102-112 teeth. The flippers are broad and almost triangular with sharply angulated front and serrated trailing edge, the internal bones is visible through the skin. The fin has a long base and a slightly rounded tip. The body tapers to the tail root. The Fluke is up to one third of body length extremely wide, has a slightly concave trailing edge and a slight indentation in the middle. Young animals have a much shorter snout and are about 70 to 80 cm long and 7.3 to 8.5 kg at birth.

Dissemination

The La Plata dolphin comes along the South American coast from about the Rio Doce in Brazil to Bahia Blanca in Argentina before. He considers himself primarily in shallow coastal waters and estuaries, but hardly penetrates ago in rivers. The most common way is sighted the mouth of the Río de la Plata, where she, however in winter rarely staying.

Way of life

The La Plata dolphin feeds on fish, squid and crustaceans. He probably browsing on his prey, he ransacked by the muddy ground with its long snout. As a loner, he avoids the presence of his peers. His dives are short, and even shorter are its stays on the surface. Because of its hidden life he is hardly seen by people. However, about 1500 La Plata dolphins caught annually in fishing nets; these are then processed for lamp oil and pig feed. It is feared that the population for this shrinkage is not long withstand, without damage.

System

The systematics of river dolphins is controversial. While previously all members of this group were considered to be convergent and not related to each other, one goes after molecular genetic studies now assume that the Amazon river dolphin, and probably also the possibly already extinct Yangtze River dolphin with the La Plata dolphin are related and a shared family that Iniidae form.

Evidence

• Mark Carwardine: whales and dolphins. Delius Klasing, Bielefeld 2008, ISBN 978-3-7688-2473-6, pp. 234-235.