Scientific Name
Balaenoptera Musculus
Life Expectancy
70+ Years


3 tons (2,722 kg)
23-27 feet (7-8.2m)


150 tons (136,000 kg)
75-90 feet (23-27.4m)


100 tons (99,800 kg)
70-80 feet (23-24.5m)

The blue whale is the largest mammal and possibly the largest animal ever on earth. Blue whales are in the rorqual family, which includes humpbacks, fin, Bryde’s, sei, and minke whales.

Blue whales are the largest baleen whale and the largest rorqual. They can grow up too 100 feet (30.5m) and weigh around 160 tons. These physical measures for a land animal would crush the animal, however, since blue whales are in the water their body is able to support their enormous size.

Blue whale hearts are the size of a Volkswagen Beetle and their main blood vessel is large enough to fit a person inside! Their heart pump 10 tons of blood throughout their body. Their spouts, which can be up to 30 feet (9.1 m) high, makes it easy to identify them on the water and from shore.

They can communicate with each other for over a hundred miles using low-frequency long distance sounds. The sounds are deep and rumble and can be heard but also felt.


The best way to spot a blue whale is by its tall, columnar-shaped blow, which can rise 30 feet high!


The best time to watch for blue whales along The Whale Trail is in the summer, when they migrate north from southern calving and breeding grounds. Blue whales return each year to the central California coast, attracted by summer krill blooms. They are less commonly seen from shore.


Blue whales are found in all oceans of the word, except the Arctic. They feed throughout their range, in mostly higher latitudes in the polar regions but will also feed in tropical waters. They migrate to temperate/tropical waters during the winter months to mate and give birth. There are five recognized subspecies of blue whales.


Blue whales have a very long, streamlined body with a smaller head than most whales. Their rostrum is broad, flat and in a U-shape that almost extends all the way to the blowhole.

Coloration. They are blue/gray in color and some spots of light gray. This color pattern can be used to identify individuals. The underside of the fluke is dark, while the underside of the flippers are white.

While in the waters of the Antarctic or North Pacific/Atlantic they acquire diatoms, microorganisms, which give the body a yellowish color. Early whalers called them “sulfur bottom” due to this yellowish color.

Dorsal Fin. Their dorsal fin is small, triangular and located in the last fourth of their body, further back than most whales. The dorsal fin is around one foot (30 cm) in length and their flippers are relatively short, compared to overall body length, only 12% of body length.

Sexual Maturity. Blue whales become sexually mature between 5-10 years of age. The females are around 79 feet (24 m) and males around 74 feet (23 m) when they start to mate.

Females have a gestation period of around 11 months and give birth every 2-4 years. The calf will nurse for 7-8 months and are weaned when they reach around 52 feet (16m) in length. They weigh around 23 tons (20,900 kg) and consume 100 gallons (379 liters) of mother’s milk every day. Blue whale calves are able to gain 200 pounds (91 kg) a day, which is the equivalent to 8 pounds (3.6 kg) per hour. The bond between a mother and calf is very close and the pair can be seen swimming very close together.

Females are larger than males. The blue whales in the Southern Hemisphere are larger than blue whales in the Northern Hemisphere and are closer to 90-100 feet in length. The largest blue whale recorded was a 108-foot female who was caught in Antarctic by a whaling ship.


Blue whales are more commonly seen in pairs or alone, however can also be seen in small groups. They are some of the loudest animals in the world and their vocalizations can be heard up to 1,000 miles away. They use pulses, groans, and moans to not only communicate but also for sonar to navigate the ocean depths.


Blue whales face threats from natural causes, predation from killer whales, ship strikes, entanglement in fishing gear, ocean noise and pollution.


Blue whales are listed as endangered under the Endangered Species Act. Their population numbers have not recovered since they were hunted to near extinction in the 1900s. Due to their large size and swimming ability, they were not pursued by earlier whalers in the 1800s. However, with an increase in technology and technique for harpooning whales, the blue whales started to be a major target for the whaling industry. Blue whales were highly sought after due to their large size and one blue whale could yield up to 120 barrels of oil. In one season, 29,000 blue whales were killed. The International Whaling Commission banned hunting of blue whales in 1966 and since then recovery has been slow. Up to 99% of the blue whales were killed by the whaling efforts and their population went from 350,000 to almost extinct. Today it is thought there are 5,000-10,000 in the Southern Hemisphere and 3,000-4,000 in the Northern Hemisphere.


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