Blue Whales: The Largest Animal Ever to Live on Earth

The blue whale (Balaenoptera musculus) is not just the largest animal alive — it is the largest animal ever to have existed on Earth, surpassing even the largest dinosaurs. Everything about a blue whale is staggering in scale.

How Big Is a Blue Whale?

Blue whales can reach up to 100 feet (30 m) in length — about the length of three school buses — and weigh up to 330,000 lbs (150 tonnes). Their heart alone is the size of a small car and can weigh 400 lbs. Their tongue weighs as much as an elephant. Newborn blue whale calves are already 25 feet long at birth.

What Do Blue Whales Eat?

Despite being the largest animal alive, blue whales eat some of the smallest: krill (tiny shrimp-like crustaceans). A blue whale can eat up to 8,000 lbs of krill per day during feeding season. They are baleen whales — they lunge into krill swarms with their mouth open, engulfing massive amounts of water and krill, then push water out through baleen plates that filter the krill.

How Loud Is a Blue Whale?

Blue whales produce the loudest sounds of any animal on Earth — their low-frequency calls can reach 188 decibels (louder than a jet engine) and travel up to 1,000 miles through the ocean. These calls are used for communication and possibly navigation.

Are Blue Whales Endangered?

Blue whales are listed as Endangered. Commercial whaling in the 20th century reduced their population from 300,000 to just 10,000–25,000 today. Main current threats are ship strikes and fishing net entanglement. Recovery has been slow because blue whales have calves only every 2–3 years.

Amazing Blue Whale Facts

• A blue whale's heartbeat can be detected 2 miles away.
• Blue whales live up to 90 years — their age can be read from earwax plugs like tree rings.
• Despite their size, blue whales can swim at 20 mph when threatened.
• Blue whale calves gain 200 lbs per day during nursing, drinking 150 gallons of mother's milk daily.