Sei Whale

Fascinating facts about the Sei Whale

• At 50 kilometres per hour, the sei whale is the fastest whale on Earth — faster than a cheetah on land. They hit this speed in short bursts to chase down swarms of krill, accelerating through the water like a missile. No other baleen whale can match them, which is why they were hunted last: whalers couldn't catch the others, so sei whales became the target of desperation.
• A sei whale's heart weighs 400 kilograms — about the same as a baby grand piano. Yet their entire skeleton is made of bone so porous it's almost sponge-like, kept light enough to power those explosive sprints. They are built like a Formula 1 car: extreme power paired with minimum weight.
• Their feeding strategy is a violent ballet: they barrel through a patch of krill at full speed with their mouths open, scooping up 300 litres of water in seconds, then expelling it through baleen plates while their tongue — heavier than an elephant — pushes the catch down their throat. A single feeding lunge can net 2 kilograms of food in under 10 seconds.
• Sei whales were nearly wiped out in just 20 years. Between 1965 and 1985, whalers killed roughly 28,000 sei whales as industrial fleets exhausted larger species first. Today, populations have stabilised at around 80,000, but they remain one of the ocean's rarest great whales — a reminder that whaling's collapse happened within living memory.
• They migrate up to 25,000 kilometres annually, moving from polar feeding grounds to tropical breeding grounds following the seasonal bloom of their prey. Unlike humpbacks, which are predictable, sei whales are nomadic: they appear and vanish unpredictably, hunting wherever plankton explodes. This makes them almost impossible to study and nearly impossible to count with certainty.

At a glance

About the Sei Whale

In the dark, mysterious depths of the open ocean, the sei whale glides effortlessly, its sleek, grey form undulating through the waves with a mesmerizing rhythm. As it moves, the whale's pectoral fins slice through the water, propelling it forward with a speed and agility that belies its massive size, making it one of the fastest swimming whales on the planet. With its very existence threatened by the perils of human activity, the sei whale remains a poignant and elusive marvel, a fleeting glimpse of which is a privilege afforded to only a select few.

Discover more wildlife