Quick Answer
The blue whale has the largest heart of any animal that has ever lived. A blue whale’s heart can weigh around 400 pounds (180 kg) and is roughly the size of a small golf cart. Its massive size helps pump blood through the whale’s enormous body, which can exceed 100 feet in length.
Despite its massive size, the blue whale’s heart beats surprisingly slowly — sometimes only a few beats per minute during deep dives.
Blue Whale Heart Quick Facts
| Feature | Blue Whale Heart |
|---|---|
| Weight | Up to ~400 lbs (180 kg) |
| Size | About the size of a golf cart |
| Aorta diameter | About 9 inches (23 cm) |
| Heart rate while diving | 2–10 beats per minute |
| Heart rate at surface | 25–37 beats per minute |
According to research from NOAA Fisheries, the blue whale is the largest animal known to have ever existed on Earth, and its cardiovascular system is adapted to support this enormous body size.
How Big Is a Blue Whale’s Heart?
A blue whale’s heart is enormous compared to that of other animals.
Scientists estimate that the heart weighs approximately 400 pounds and measures roughly 5 feet tall. Because the whale’s body can exceed 100 feet in length, a massive heart is required to pump blood throughout its entire body.
Heart Size Comparison
| Animal | Heart Weight |
|---|---|
| Human | ~10 ounces |
| Dolphin | ~3–5 lbs |
| Elephant | ~60 lbs |
| Blue whale | ~400 lbs |
This enormous heart allows the whale to maintain circulation across an incredibly large body mass.
Massive Blood Vessels
The blue whale’s arteries are also extremely large in order to carry blood efficiently throughout the whale’s body.
The whale’s aorta — the main artery leaving the heart — can measure roughly 9 inches in diameter.
These large arteries allow oxygen-rich blood to reach the whale’s brain, muscles, and vital organs while the animal is diving deep underwater.
According to marine biologists studying whale anatomy, the circulatory system of large whales is highly specialized to maintain oxygen delivery during extended dives.
Blue Whale Heart Rate
Despite the whale’s large size, its heart beats surprisingly slowly.
| Situation | Heart Rate |
|---|---|
| Deep diving | 2–10 beats per minute |
| At the surface | 25–37 beats per minute |
When the whale dives, its heart rate slows dramatically. This process helps conserve oxygen while the whale remains underwater.
When the whale surfaces to breathe, its heart rate increases again to circulate oxygen throughout the body.
This adaptation allows whales to stay underwater for long periods before returning to the surface to breathe. Learn more in our article on how whales breathe.
Why Blue Whales Need Such a Large Heart
The blue whale is the largest animal to ever live, even larger than the largest dinosaurs.
Adult blue whales typically measure:
- 70–90 feet long on average
- 100–150 tons in weight
- Over 100 feet long in the largest recorded individuals
Because of this enormous body size, the whale requires an extremely powerful heart to circulate blood across long distances.
The cardiovascular system works together with the whale’s lungs and muscles to store oxygen efficiently during deep dives.
Other Fascinating Blue Whale Facts
Blue whales are not only known for their enormous hearts — nearly every aspect of their biology is massive.
- A newborn blue whale calf can measure about 25 feet long at birth.
- A calf can drink up to 150 gallons of milk per day.
- Young blue whales may gain up to 200 pounds per day during early growth.
Adult blue whales feed primarily on krill, tiny shrimp-like animals that form large swarms in the ocean.
A single blue whale can eat up to 8,000 pounds of krill per day, which may equal roughly 40 million individual krill.
During long migration periods, blue whales may rely heavily on stored energy within their blubber.
According to the World Wildlife Fund, blue whales are found in oceans worldwide and migrate long distances between feeding and breeding areas.
Blue Whale Size Comparison
| Animal | Average Length |
|---|---|
| Blue Whale | 70–100 ft |
| Killer Whale | 20–26 ft |
| Great White Shark | 15–20 ft |
| African Elephant | 20–25 ft |
Even the largest land animals are far smaller than the blue whale.
Frequently Asked Questions
How big is a blue whale’s heart?
A blue whale’s heart can weigh about 400 pounds and is roughly the size of a small golf cart.
How slow does a blue whale’s heart beat?
During deep dives, a blue whale’s heart rate may drop as low as 2 beats per minute.
Can a human swim through a blue whale artery?
Some large arteries in whales are extremely wide, but the commonly repeated claim that a human can swim through them is debated by scientists.
Why do whales have slow heart rates?
Slow heart rates help whales conserve oxygen during long dives underwater.