Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Balaenopteridae
Genus: Balaenoptera
Species: B. musculus
Subspecies: B. m. brevicauda
Trinomial name: Balaenoptera musculus brevicauda
Common name: Pigmy blue whale
The Pygmy blue whale differs from the "true" blue whales in a number of physical characteristics. It has broader and shorter baleen plates, a shorter tail, and hence a proportionately longer body in front of the dorsal fin, a larger head relative to body size, and, a heavier body weight compared to other blue whales of the same length.
Pygmy blue whales adults average >22.5 meters. The average weight is 75.5 tonnes for males and 90 tonnes for females. Pygmy blue whales also tend to be darker than the other subspecies of blue whales, and the shape of their blowhole is different.
Te Papa the Museum of New Zealand has a complete 20.6-metre skeleton of a male subadult (adolescent) pygmy blue whale hanging in an exhibition. It was a whale which was hit by a container ship off the North Cape of New Zealand in 1994. It is thought that the whale was probably resting at the surface after an attack by killer whales when it was struck. Scratches on its body were evidence of the attack. The impact of the ship smashed some of its ribs and left the dead animal wrapped around the ship’s bow. The whale was towed to Motutapu Island in Auckland Harbour where it was hauled ashore and its flesh and blubber cutaway (‘flensed’). The bones were then enclosed in sea cages where sea lice (little meat-eating crustaceans) cleaned off the remaining flesh. The whole skeleton was re-assembled at Te Papa in October 1996.
The Pygmy blue (Balaenoptera musculus brevicauda) are long, slender, streamlined whales with a flat head and mouth about six metres long. They have a slate-blue head and upper body but a lighter underbody. Their back and sides are faintly mottled. With a heart as big as a small motor car, ten tonnes of blood pumps around their bodies. Their biggest arteries are so big that a child could crawl through them. Their brains alone weigh about seven kilograms, and an entire whale can weigh in at ninety tonnes. They have the same large bulbous head containing spermaceti oil.
Small numbers of Pygmy blue whales continue to be killed by Japanese and Indonesian whalers.
Text thanks to Te Papa the Museum of New Zealand.
Photo of a Pygmy Blue Whale that washed ashore at Cathedral Rock, near Lorne in western Victoria, in 1992. Its skeleton is on display at the Melbourne, Museum
Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/
