Fin whale

Balaenoptera physalus


Size: max 26m

Key feature: Long body, and tall blow

Fin whales are the second largest animals on the planet, reaching 26m in length. They have a long, thin grey body with a white underbelly. They have an asymmetrical colouration on their lower jaw, with a dark left side and white right side, an adaptation that aids their feeding strategy. Fin whales are often confused with the sei whale, but fin whales are longer in length and have a smaller fin which is further back on their body. They have a very tall blow which, on a clear day, can be seen all the way on the horizon.


They are typically seen on their own or in groups of up to 7 individuals. They are the fastest cetacean, swimming up to 37 km per hour. They often feed below the surface but can occasionally be seen lunge feeding at the surface. They can also be mistaken for a blue whale but can be distinguished when they dive as they do not raise their fins, and are grey rather than in blue in colour.


Fin whales have a global distribution; they stay in subtropical and temperate waters during the summer and tend to move to more tropical areas in the winter. They can be seen in the Bay of Biscay, particularly in the late summer, with peak sightings in August. They are pelagic but are also known to go into shallower waters, as low as 30m in depth. 


Fin whales have been commercially hunted for their blubber, oil and baleen. Between 1935 and 1965 30,000 fin whales were killed every year. Whaling was banned in 1986, however there are worries that fin whale populations may never be able to recover to their pre-whaling numbers. Current threats include ship-strikes, noise pollution, chemical pollution and entanglement in fishing gear.

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