How much does a blue whale weigh?

Blue Whale Weight: The Heaviest Animal in History

Blue whales (Balaenoptera musculus) are not only the longest animals on Earth — they are also the heaviest. An adult blue whale can weigh up to 200 tons (400,000 pounds), though most adults fall in the range of 100 to 150 tons. No animal in the fossil record, including the largest dinosaurs, is known to have exceeded the weight of a large blue whale.

Average and Maximum Weights

Blue whale weight varies based on sex, age, season, and geographic population:

• Adult females: Typically 100 to 150 tons. Females are generally heavier than males.
• Adult males: Typically 90 to 130 tons.
• Maximum recorded: Approximately 190 tons (173 metric tonnes), though weights above 150 tons are exceptional.
• Newborn calves: About 3 tons (2,700 kg or 6,000 pounds) at birth.

Weighing a blue whale is extremely difficult in practice. Most weight estimates come from whaling records, where animals were weighed in pieces, or from mathematical models based on length measurements.

Weight of Individual Body Parts

The enormous total weight of a blue whale is reflected in its individual organs and structures:

Body Part	Approximate Weight
Heart	400 lbs (180 kg)
Tongue	6,000 lbs (2,700 kg)
Stomach (full)	~2,200 lbs (1,000 kg)
Blubber layer	15-30% of total body weight
Blood volume	~2,500 gallons (9,500 liters)

A blue whale’s tongue alone weighs as much as an African elephant. Its heart is roughly the size of a small car and pumps approximately 60 gallons (227 liters) of blood with each beat.

How Blue Whales Gain and Lose Weight

Blue whale weight fluctuates dramatically throughout the year due to their migratory feeding cycle:

1. Summer feeding season: Blue whales spend summers in cold, nutrient-rich polar waters where krill is abundant. During this period, a blue whale can consume up to 4 tons of krill per day, rapidly building up thick layers of energy-rich blubber.

2. Winter breeding season: Blue whales migrate to warmer tropical or subtropical waters to breed and give birth. During this period, they eat very little — sometimes nothing at all for months — and rely on their fat reserves. A blue whale may lose 25 to 30 percent of its body weight during the winter months.

How Blue Whales Compare to Other Heavy Animals

To appreciate how extraordinary blue whale weight is, consider these comparisons:

• A blue whale weighs as much as 25 to 30 adult African elephants (the largest land animal).
• A blue whale weighs roughly the same as 15 school buses.
• The largest known dinosaur, Argentinosaurus, weighed an estimated 70 to 80 tons — less than half the weight of a large blue whale.
• A humpback whale weighs about 40 tons, roughly a quarter of a blue whale’s weight.

Why Can Blue Whales Be So Heavy?

Water buoyancy is the key factor that allows blue whales to reach such extreme weights. On land, an animal of this size would be crushed by its own weight — its skeleton and muscles simply could not support 200 tons against gravity. In water, buoyancy offsets most of that weight, allowing the whale’s skeleton to be relatively lightweight compared to its total body mass.

The availability of krill in vast quantities also supports this enormous body size. Blue whales evolved to be the ultimate krill-harvesting machines, and their size allows them to engulf huge volumes of water with each feeding lunge.