Risso's Dolphin

Fascinating facts about the Risso's Dolphin

• A Risso's dolphin's skin tells the story of its life like a scar map. Calves are born dark grey, but by adulthood they're covered in white scratches and bite marks from wrestling with squid and sparring with rivals — some individuals are so scarred they look almost white. These marks are battle honours from decades hunting giant squid in the open ocean, sometimes diving deeper than 600 metres to find them.
• Unlike most dolphins that hunt fish in coordinated pods, Risso's dolphins are squid specialists with a hunting style closer to deep-sea divers than reef hunters. A single dolphin can descend 300 metres to pursue a squid and hold its breath for up to 30 minutes — longer than almost any other dolphin species. This shift from surface prey to deep-water squid shaped their entire body: larger brains, slower growth, and lifespans stretching past 35 years.
• A Risso's dolphin has no dorsal fin in the traditional sense — just a tall, triangular ridge that angles backward like a weathered sailboat's mast. This unusual shape is thought to reduce drag during their deep, prolonged dives after squid in the open ocean. The ridge also serves as a social flag: larger males develop taller, more prominent ridges, advertising dominance to rivals and females in the featureless ocean.
• They live in the loneliest habitat of any dolphin — the open ocean, sometimes hundreds of kilometres from land, where they hunt in loose groups of 10 to 30 individuals rather than the tight pods of coastal dolphins. Risso's dolphins are found in every temperate ocean from Japan to the Atlantic, but they're rarely seen from shore. Most of what we know about their behaviour comes from brief encounters with research vessels in the middle of nowhere.
• A newborn Risso's dolphin nurses for up to 2 years — longer than any other dolphin in temperate waters — and mothers invest so heavily in each calf that they often space births 3 to 4 years apart. This slow reproduction rate means populations recover slowly from hunting or disease, and it reveals why they evolved such long lifespans: in the food-scarce open ocean, living 35+ years allows females to raise only 4 or 5 calves in a lifetime, betting on quality over quantity.

At a glance

About the Risso's Dolphin

In the dark, mysterious depths of the ocean, the Risso's Dolphin glides with effortless elegance, its scarred and weathered body a testament to a life of curious exploration and social intrigue. As it moves through the waves, its dorsal fin slices the surface with a gentle whoosh, leaving behind a trail of rippling water that belies the complexity of its underwater world. With a reputation for intelligence and playfulness, this enigmatic creature navigates the ocean's twilight zones, its clicks and whistles echoing through the darkness like a haunting melody.

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