Fin Whale – Balaenoptera physalus


The Fin Whale, also known as Finback Whale, Razorback or Common Rorqual, belongs to the family of the rorquals (Balaenopteridae) and thus is part of the infraorder of the Whales (Cetacea). Balaenoptera physalus was first described in 1758 by Linnaeus.

Some zoologists distinguish the populations of the northern and southern hemisphere into two subspecies, the Northern Fin Whale (Balaenoptera physalus physalus) and the Southern Fin Whale (Balaenoptera physalus quoyi). Thereby the southern population becomes about 10% larger than the northern one.

Description

The Fin Whale is relatively slender and therefore weighs less than a Blue Whale at the same length. It also weighs less than many smaller whales. Its maximum length is 27m, with females being in average slightly larger. The maximum weight is 70t.

The colouration of Balaenoptera physalus is dark grey to black or brown at the back, while the abdomen and underside of Flipper and Fluke are white. The best identification feature is the asymmetrical colour distribution at the front body section. On the right the lower jaw is white, while on the left it is dark.

Habitat and Distribution

Cetacea range map Fin Whale.PNG
CC BY-SA 3.0, Link

The Fin Whale is widely distributed in all oceans, avoiding small seas with narrow access. However, this does not apply to the Mediterranean Sea. While spending winter in temperate and subtropical zones, it migrates to the polar regions in the summer.

Due to the opposite seasons of the northern and southern hemisphere, the two populations never meet at the equator.

Biology

Because Balaenoptera physalus belongs to the parvorder of the Baleen Whales, it feeds mainly on krill. In addition, it also happens that it chases small fish. When hunting, it dives in depths of about 200m and reaches dive times of 15 minutes. During hunting, it absorbs 60 to 82 tons of seawater at a time, doubling its volume. In addition, it consumes up to 2 tons of food per day.

The Fin Whale is usually found alone or in small groups of about 6 animals. Large groups are also sighted locally at certain events.

Sources

http://www.marinespecies.org/

https://en.wikipedia.org/

https://de.wikipedia.org/