Atlantic white-sided dolphin

The Atlantic white-sided dolphin (Leucopleurus acutus, formerly Lagenorhynchus acutus) is a distinctively coloured dolphin of the cool to temperate waters of the North Atlantic Ocean, where it is endemic. Its range runs from the Norwegian Sea and the Davis Strait south to coastal North Carolina and the Celtic Sea, with particularly dense populations off Newfoundland and Cape Cod, in the sea between the United Kingdom, Iceland and Greenland, and in the northern North Sea. Adult males grow to about 2.8 metres and females to about 2.5 metres, weighing between 180 and 230 kilograms. A white to pale yellow patch behind the dorsal fin on each side marks the species against a dark gray to black back and a white chin, throat and belly. It feeds mainly on herring, hake, mackerel and squid, sometimes hunting cooperatively near the surface, and travels in social pods that average around 50 animals. John Edward Gray named it in 1828, and in 2025 it was moved from Lagenorhynchus to its own genus.