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  • Fin whale biology

Fin Whale facts

The Zoology Museum was designed so that the Whale, an important teaching specimen, should also advertise the Museum’s presence. The original iron framework was used in the reassembly of the skeleton in its 1996 location above the Museum’s old main entrance, where it was spotlit. The skeleton is spectacular, with a length of 21 m. The living animal would have weighed around 80 tonnes (around the same size as the heaviest dinosaurs).

Whales, dolphins and porpoises comprise an order of mammals called the Cetacea. Quite recent finds of fossils indicate that, as long suspected, the closest living relatives to the whales, dolphins and porpoises are the even-toed ungulates (such as pigs, hippopotamuses, giraffes, camels, antelope, deer and cattle).

Various colloquial names have been given to Balaenoptera physalus (the correct zoological name for this particular whale): it is most frequently called ‘Fin Whale’ or ‘Finback Whale’, but ‘Common Rorqual’ and ‘Razorback’ have also been used. The latter name reflects the conspicuous ridge on the hind part of the back. The family to which Fin Whales belong, the Balaenopteridae, also contains the Blue Whale, Bryde’s Whale, the Sei Whale, the Humpback Whale, and the Minke Whale. All of these, together with whales in three other related, living families are mysticetes, that is, so-called ‘whalebone’ or ‘baleen’ whales, with fringed plates in their mouths to strain out food material from the water. The other major grouping of whales, the odontocetes, or ‘toothed whales’, includes a variety of large-bodied forms, such as Sperm Whales, together with the dolphins and porpoises. There are other differences between the two major groupings of whales; for example, whalebone whales have two blowholes, whereas toothed whales have only one. The two sorts of whales, toothed and whalebone, appear to have been separate since at least 40 million years ago.

In life, Fin Whales are usually grey or brownish on their backs and pale on their bellies, with a short fin on the back quite close to the animal’s tail. There is an interesting asymmetry in colouration: the right side of the jaw is pale, whereas the left side is darker. This asymmetry of pigmentation is also shown on the tongue.

Fin Whales occur in small groups or may be solitary. They are typically whales of the open seas and are found in all oceans. They are very fast-swimming whales, and show similar migratory habits to Blue Whales, with a general northwards movement of southern animals into warmer waters for breeding during the southern winter season. However, Fin Whales return to the Antarctic somewhat later than Blue Whales.

They eat small crustaceans and schooling fishes such as herring, together with squid. Like other whalebone whales, Fin Whales feed by using their baleen, the fringed plates on both sides of the mouth, as a strainer. There may be over four hundred plates on each side, each some seventy centimetres long. These plates are on the upper jaws only. The lower jaws are bowed outwards, and are joined together by ligaments at their front ends, to give some flexibility of movement. The throats of whalebone whales are grooved, longitudinally, indicating the presence of pleats that allow an enormous expansion of the throat cavity when water is taken in. The mouth, itself, can be opened very wide and, together with the expansion of the throat, tonnes of water are strained through the baleen every time the animal takes a mouthful.

Fin Whales become sexually mature at around ten to thirteen years old. Calves are born after an eleven-month period of gestation, and are suckled for about six months. At birth a Fin Whale calf weighs a mere 1.8 tonnes, and is around 6.5 metres long.