Length and Weight
It is difficult to measure a blue whale’s size because this ocean creature is such a giant! Therefore, only approximate measurements are possible. This explains why the length and weight results provided by scientists and whalers differ somewhat.
Average male length: 25 m
The largest individuals have been estimated at being 150-200 tonnes and measured up to 29 m in length.
At birth, the calf is about 7 m long and weighs around 5000 – 6000 pounds (2700 kg). That is about as much as 10 adult grizzly bears!
Body and Fins
Blue whales have a long, slender body. This streamlined shape allows the whales to move efficiently through the water. They are fast swimmers and it is said that they can reach a maximum speed of about 20 mph (30 km/h). But usually they cruise along at a slower speed.
The dorsal fin is small and far back. It has a triangular or sickle-shaped form.
The pectoral fins (flippers) are short, dark coloured on top and light coloured underneath.
The caudal fin has two flukes on each side. Its size ranges from 6.5 to 7.5 m (21 – 25 ft). The tips of the flukes are pointed and the point where they meet is deeply notched. The upper-side and under-side are both dark coloured.
The whales are greyish, light bluish in colour with lighter and darker mottling. Every whale has a distinct mottling pattern (like a finger-print) and therefore these patterns are often used to identify individual whales.
Sometimes the whales have unique skin markings that also help to identify individuals. Skin markings include various skin lesions; peeling skin, rake marks from killer whales,
cookiecutter shark bite marks, scars from ship strikes, from fishing gear and ocean debris entanglements.
Blue whales typically have 260 to 400 baleen plates on both sides of the upper jaw. The plates are as long as 90 cm (35.5 inches).
Dive and Breathing Sequences
IUCN Status: Endangered
IUCN Population trend: Increasing
CITES: Appendix I
CMS: Appendix I