Blue Whale Facts: Lesson for Kids

Lauren Scott

Lauren has a Bachelor's degree in biology from Virginia Tech and Master's degrees in environmental science & policy and special education from Johns Hopkins University. She has 20 years of teaching experience in public, private, and informal educational settings.

Expert Contributor
Christianlly Cena

Christianlly has taught college physics and facilitated laboratory courses. He has a master's degree in Physics and is pursuing his doctorate study.

This lesson will teach you about the magnificent blue whale. You will learn important facts, like where blue whales live, how they eat, and why they need to be protected. Updated: 11/21/2020

Blue Whale Basics

Imagine an animal so large that its heart weighs as much as a small car. Picture it pushing thousands of pounds of food down its throat with a tongue that weighs as much as an elephant. This may sound like science fiction, but it's reality for the massive blue whale.

A blue whale may grow to 100 feet in length.
Blue whale

The blue whale is the largest animal in the history of the world. It can grow to a length of 100 feet and 200 tons. It has a long, blue-gray body with a small dorsal fin on its back. The blue whale uses its tail fin, called the fluke, to swim through the ocean at speeds of over 20 miles per hour.

Blue whales do not breathe through gills like fish--they use lungs to breathe air at the surface of the ocean. Many people think whales blow water out of their blowholes, but it's really just air mixed with a little water from the surface.

A small section of baleen

The Lives of Blue Whales

Blue whales are found in oceans all over the world, usually in groups called pods. They spend summer near the poles, where they can easily find food. Winter is spent in warmer waters, where they mate.

Females give birth to single babies, called calves. These calves are some of the biggest babies on the planet! A newborn calf is up to 25 feet long and 3 tons. It gains 200 pounds a day for the first year of its life just by drinking its mother's milk.

Nobody knows exactly how long blue whales live, but scientists believe they live more than 50 years. They have few predators but are occasionally attacked by killer whales and sharks.

A Very Tiny Meal

Despite their enormous size, blue whales feast on some of the tiniest animals in the sea: shrimp-like animals called krill. That's because they don't have teeth. Instead, they use rows of bristles on their upper jaws, called baleen. The whale opens its wide mouth and takes in thousands of gallons of water. Then, the whale strains the water out through its baleen and eats the krill left behind.

Blue whales can eat 8,000 pounds of krill each day. They need these huge meals because they go for several months without eating during breeding season. And since they burn about 3 million calories per day, they really need to store their energy!

Krill are tiny, shrimp-like animals.

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Additional Activities

Blue Whales: Fill-in-the-Blank Activity

This activity will help you assess your knowledge of the diet, habitat, and status of blue whales in our vast oceans.


For this activity, print or copy this page on a blank piece of paper. Use the words presented in the word bank to complete the sentence. Neatly write them on the appropriate blank space provided.


  1. Blue whales are named for their __________ to blue skin coloration, which appears true blue underwater.
  2. Blue whales can reach a length of 100 feet and a weight of 200 tons, making them the __________ animal on the planet.
  3. The bony material that makes up the plates in the upper jaw of a blue whale is called the __________.
  4. __________ refers to a species of small, shrimp-like organisms that serve as the major food source of whales.
  5. __________ is the process of hunting whales for their usable products such as meat and oil.
  6. Whales are a widely distributed and diverse group of fully aquatic animals, which breathe air through their __________.
  7. A baby blue whale depends primarily on its mother's __________ for survival.
  8. __________ strikes and __________ entanglement are significant mortality factors for blue whales.
  9. Blue whales are formally classified as __________ animals by various international organizations.
  10. Some animals, including the blue whale, can go for several months without eating during the __________ season.

Word Bank

Answer Key

  1. Gray
  2. Largest
  3. Baleen
  4. Krill
  5. Whaling
  6. Blowholes
  7. Milk
  8. Ship, Fishing gear
  9. Endangered
  10. Breeding

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