Peale's Dolphin: Lagenorhynchus australis

Abstract

Peale's dolphin (Lagenorhynchus australis) is common in inshore waters of southernmost South America, but because it seldom strands, its natural history is not well known. Nearly a century passed before the first descriptions of its pigmentation and a museum skull were discovered to be of the same species. Peale's dolphins are dark gray or black on the dorsal surface, with two areas of lighter pigmentation on the sides. A curved white-to-gray flank patch angles forward from the vent, narrowing to a single line ending below or in front of the dorsal fin. The posterior curves of the flank patch almost meet above the tail stock. The larger thoracic patch is light-to-medium gray, outlined with a narrow dark line on its lower surface. Peale's dolphins can be confused with dusky dolphins, L. obscurus, throughout much of their range. Peale's dolphins occupy two major habitats: open coasts over the shallow continental shelf of the eastern coast of Patagonia and Tierra del Fuego and Chile north of Chiloè; and the deep, protected bays, and intricate channels of southern Chile. Peale's dolphins are most often seen swimming slowly in or near the kelp. They commonly bow ride, with much head movement, rolling, breaching, spy hopping, and spinning. They produce a wide splash when surface swimming, earning the name “plough-share” dolphins. Kelp forests seem to be a fundamental habitat for Peale's dolphins in coastal ecosystems and their protection may be crucial for the conservation of this species.