Sei Whale (Balaenoptera borealis) lives in open ocean across All oceans worldwide. It feeds on krill & plankton. Its conservation status is Endangered.
Fascinating facts about the Sei Whale
- Speedy as a sprinting cheetah, sei whales can burst to 50-55 km/h (31-34 mph) for short distances. That makes them one of the fastest cetaceans, able to outrun many predators and quickly reach rich feeding patches, showing how agility helps survival even at massive size.
- Weighing up to 28 tonnes and stretching 19.5 m (64 ft) long, the sei whale ranks third among rorquals, just behind the blue and fin whales. Their sheer bulk lets them filter roughly 900 kg (2,000 lb) of zooplankton daily, turning tiny prey into a massive energy source for the ocean's food web.
- Each sei whale carries 300-380 ashy-black baleen plates up to 80 cm (31 in) long, with bristles only 0.1 mm thick, the finest of any rorqual. This ultra-fine filter acts like a microscopic sieve, allowing the whale to capture the tiniest copepods and krill that larger, coarser baleen would miss.
- After more than 255,000 individuals were killed by commercial whaling in the 19th-20th centuries, sei whales are now protected and listed as endangered. Populations are slowly rebounding, especially in the Northern Hemisphere (CITES Appendix II), highlighting how legal safeguards can help restore a once-decimated giant.
- Sei whales migrate annually, spending summer in cool sub-polar waters and winter in temperate, subtropical seas, and can live up to 70 years.
Sources
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At a glance
RangeAll oceans worldwide
HabitatOpen ocean
DietKrill & plankton
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.
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