Fin and back
Scientific name: Balaenoptera physalus.
Fin whales are the second largest animal in the world and can reach lengths up to 27 meters in length. They are slender animals, that have grey to dark brown coloured skin, with a pale underbelly. On the lower lip, the right side is pale to white whereas the left side is dark; this is called asymmetrical pigmentation. The dorsal fin is small and normally swept back and is set back more than 2/3 of the way back towards the tail. The blow is strong, tall, columnar, and lingers for several seconds.
Habitat and distribution
The worldwide distribution of the Fin whale is between 50,000 and 90,000. They are often seen in deen open ocean, and it is thought that they migrate between feeding and mating grounds.
Fin whales tend to be solitary or in pods of 2 to 8. Their blow sequences are normally 4 to 5 blows 10 to 20 seconds apart, followed by a deep dive of about 5 to 5 minutes. When they dive, the tail is strongly arched, though flukes are almost never shown. Fin whales have been breaching 2/3 of the whale appears at around a 45° angle, causing a big splash on re-entering the water.
They have been seen feeding at the surface when they lunge through prey concentrations often on their side with a large disturbance of the sea surface. Despite being shy, fin whales have been seen interacting with other cetaceans, including dolphins and blue whales.
Confusion with other species
Sei whale: similar in appearance at sea, but has a tall, more erect dorsal fin that is set more forward on the back that shows at the same time as the blow.
Blue whale: huge whale that is a bluey grey and has a small dorsal fin.
Humpback whale: has a hump in front of the dorsal fin and their blow is much bushier.
Minke whale: similar shape and colour but is much smaller, their blow is rarely seen, and they have white patches on the pectoral fins.
In the 20th century, fin whales were heavily targeted by whaling ships with exploring harpoons. Exact data is not known, but it is estimated that 1,000,000 fin whales were taken, 75% of these were in the southern hemisphere. Since protection was introduced the latter part of the 20th century, there has been some recovery in numbers in some populations, however whaling ships from Iceland and Japan continue to hunt for fin whales for their oil, meat and baleen.
Other threats that fin whales face are becoming entangled in fishing gear left in the oceans, and injuries from large ships and boats.
In the wild, they can live for over 100 years.