Mammals
Southern Right Whale Dolphin
Lissodelphis peronii · also called southern right whale dolphins
Gliding through cold Southern Ocean water with a completely smooth, fin-free back, a southern right whale dolphin’s bold black-and-white pattern stands out sharply, one of only two dolphin species anywhere in the world built entirely without a dorsal fin.
Overview
The southern right whale dolphin, Lissodelphis peronii, is a sleek, fin-free dolphin native to cold circumpolar waters across the Southern Hemisphere, roughly encircling the globe at temperate to subantarctic latitudes. Its complete absence of a dorsal fin, bold black-and-white colouration, and broad circumpolar distribution make it one of the more physically distinctive and geographically far-reaching dolphins found anywhere in the Southern Ocean.
A Southern Hemisphere mirror of its northern cousin
Sharing its complete lack of a dorsal fin with only one other dolphin species on Earth, the southern right whale dolphin represents a striking case of two closely related species independently occupying opposite ends of the planet’s cold waters.
Status
Least Concern overall but decreasing in parts of its range, widespread across suitable cold circumpolar habitat throughout the Southern Hemisphere.
Southern Right Whale Dolphin: common questions
How is the southern right whale dolphin related to the northern right whale dolphin?
This species and the northern right whale dolphin are the only two dolphin species in the world with no dorsal fin at all, close relatives occupying opposite hemispheres, one found in the cold North Pacific and the other across the cold, circumpolar waters of the Southern Hemisphere.
How does the southern right whale dolphin's range compare to most other dolphins?
This species occupies a broad circumpolar range across the cold waters of the Southern Hemisphere, found at similar latitudes across multiple oceans rather than being confined to one specific ocean basin, a distribution pattern quite different from many other dolphin species with more geographically limited ranges.
What does the southern right whale dolphin look like?
This species displays a bold, sharply contrasting black-and-white colour pattern with white markings along the underside and flanks standing out clearly against an otherwise dark body, combined with a notably sleek, slender, eel-like overall body shape.
Why don't right whale dolphins have a dorsal fin?
The exact evolutionary advantage of the fin-free body shape shared by both right whale dolphin species is still debated by researchers, though the streamlined profile it creates likely contributes to efficient swimming across the cold, open waters both species inhabit.