Mammals
Northern Right Whale Dolphin
Lissodelphis borealis · also called northern right whale dolphins
Skimming low across the surface of the cool North Pacific in a long, gliding leap, a northern right whale dolphin’s completely smooth back, entirely free of any dorsal fin, makes it instantly recognisable among the dolphins sharing these same offshore waters.
Overview
The northern right whale dolphin, Lissodelphis borealis, is a sleek, fin-free dolphin native to cool temperate waters across the North Pacific, from Japan to the western coast of North America. Its complete absence of a dorsal fin, unusually slender body shape, and distinctive low, skimming leap style make it one of the more physically unique and easily identifiable dolphins found anywhere in the world’s oceans.
The dolphin with no fin at all
While every other North Pacific dolphin species carries some form of dorsal fin, the northern right whale dolphin has none whatsoever, a striking anatomical absence that gives it one of the smoothest, most streamlined profiles of any dolphin in the ocean.
Status
Least Concern overall but decreasing in parts of its range, widespread across suitable cool water habitat throughout the North Pacific.
Northern Right Whale Dolphin: common questions
Why does the northern right whale dolphin have no dorsal fin?
This species is the only dolphin species in the North Pacific with no dorsal fin at all, a distinctive absence that gives its back a completely smooth, unbroken profile at the surface, though the precise evolutionary advantage of this fin-free body shape is still debated by researchers.
Why is it called the right whale dolphin?
This species gets part of its common name from a resemblance to right whales, which similarly lack a dorsal fin, a naming convention based on this shared physical absence rather than any close relationship between the small dolphin and the much larger baleen whale.
How does the northern right whale dolphin swim differently from other dolphins?
This species tends to skim low across the water surface in long, low leaps rather than the higher, more arcing jumps typical of many other dolphin species, a swimming style well suited to its notably sleek, slender, eel-like body shape.
Where does the northern right whale dolphin live?
This species is native to cool temperate waters across the North Pacific, from Japan to the western coast of North America, generally remaining in cooler offshore water rather than the warmer tropical seas favoured by some other dolphin species.