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Which is the largest whale species?

The blue whale is not only the biggest whale living today; the blue whale is the biggest creature ever to have lived on Earth. They are mind-bogglingly gigantic; much larger than any of the dinosaurs. Blue whales and the other ocean giants live their whole lives in seawater, where their bodies are fully supported. What magnificent, incredible creatures they are!

Blue whales commonly reach the colossal length of 29m (95ft), that’s roughly as long as three London red double-decker buses parked end to end, or the full length of a netball court. Blue whales in the Southern Hemisphere are generally larger than those in the Northern Hemisphere and female blues are larger than males.

The longest blue whale on record is a female measured at a South Georgia whaling station in the South Atlantic (1909); she was 33.58m (110ft 17in). The heaviest blue whale was also a female hunted in the Southern Ocean, Antarctica, on 20 March 1947. She tipped the scales at 190 tonnes (418,878 lb) which is equivalent to about 30 elephants or 2500 people.

Blue whales are now extremely rare due to uncontrolled commercial whaling. Some populations could be endangered to the point of extinction.

How big is a blue whale baby?

Not surprisingly perhaps, the biggest mothers on Earth give birth to the biggest babies; baby blue whales are truly bonny babies! A newborn blue whale is 6-8m (20-26ft) long and weighs up to three tonnes (3000kg or 6,613lb), that’s heavier than an adult male rhino. The baby feasts on mum’s fat-laden milk (it is 40-50% fat) and drinks about 250 litres (about enough to fill a bath) every day, gaining about 4kg an hour. This is the fastest growth rate of any creature on Earth; the baby gains up to 100kg (220lbs) in body weight every day. In other words the baby puts on a tonne in weight every 10 days!

A blue whale baby is weaned at 7-9 months old when they measure about 15m (49ft) from nose to tail.  The mother and baby stay together for about a year in total and the youngster will reach maturity at 5-15 years old. Blue whales are thought to live for 90 years.

Amazing facts about whales and dolphins

Dive deeper into the world of whales and dolphins and learn more about their lives.

A humpback whale pokes its head partway out of the water, a behavior called spyhopping

Facts about whales

Amazing facts about whales, the largest mammals to live on Earth.

two dolphins diving down out of the water

Facts about dolphins

From the orca to the tiny vaquita, learn more about these creatures.

Northern Resident orca, Fife, swimming at the surface

Record breakers

Whales and dolphins hold some incredible records.

Breaching North Atlantic right whale

Brain power

Just how intelligent are whales and dolphins?

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Humpback whale spyhop


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Bottlenose dolphin calf breaching with its whole body out of the water


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Breaching North Atlantic right whale


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Orca spyhop


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