Blue Whale Facts For Kids

The blue whale is the largest living animal in existence.

In fact a blue whale can measure as long as two 18 wheeler trucks!

If you’ve ever looked straight up at a 10 story building you’ll have a good idea of how long a blue whale can be.

When fully grown this massive marine mammal can reach lengths in excess of 100 ft. and weight more than 150 tons!

Even their children are big and can easily measure in at over 23 ft long at birth which is comparable in size to an adult killer whale and roughly 1/3 the length of the mothers entire body.


Despite the blue whales massive size its primary diet consists almost solely of krill, a tiny sea creature that measures in at a meager 1 – 2 centimeters on average, although some species of krill can reach a maximum length of around 6 inches.

In order to maintain their food supply (blue whales can consume as many as 40 million krill per day) these whales are often found in areas where krill is largely abundant.

Some of the locations blue whales can be found living in include Antarctica, the North Atlantic and North Pacific Oceans and the Indian Ocean.

As far as how blue whales hunt their prey the blue whale belongs to the baleen whale suborder and is known as a filter feeder.

These large whales do not have teeth like toothed whales so instead they hunt their food by swimming towards it with their mouth open and engulf as many krill as possible.

Once they’ve captured as many small krill as they can fit in their mouth they push the excess water out of their huge mouth with their tongue.

In order to keep the krill from escaping they have baleen plates with bristles attached to them.

The baleen bristles look similar to the bristles found on a comb and act as a filter by allowing water to pass through the openings while remaining packed tightly enough to prevent food from escaping.

Interestingly despite this animals massive size they have relatively small throats, so small in fact (less than 12 inches) that it would be impossible for them to swallow an average sized person.

While these whales can be seen traveling in most of the worlds major oceans they tend to prefer colder climates where large abundances of krill live in large quantities.


Depending on the time of the year these marine mammals will migrate from one location to the next in order to feed or mate.

When mating season comes around during the colder months these whales travel thousands of miles from their feeding grounds to their mating grounds and may completely forgo eating the entire trip which could last as many as four months.

During these long migration trips blue whales are very laid back and relaxed when it comes to swimming.

On average blue whales are known for traveling an average of around 5 miles per hour although they can reach speeds of up to 20 miles per hour when they feel threatened.

The slow swimming speed helps these amazingly large animals conserve their energy which is important since they eat very little or on food at all.

During mating season blue whales can be heard performing whale songs which are believed to be used by males to attract a female to mate with.

Once all of the whales mate it takes an average of 10 – 12 months for the female to give birth.

From what little is known about the blue whales mating habits it is thought that the female whale gives birth to a single offspring once every 2 – 3 years while she is fertile.

In addition mating in their mating grounds it is also the place where they give birth to their young.

The warmer temperate waters provide a stable and secure place for these whales to give birth with minimum issues.

Note: Despite being given the name “killer whale” these marine mammals are actually the largest animals in the dolphin family.

Giving birth

As stated earlier it takes an average of 10 – 12 months for a mother to give birth once she becomes pregnant.

While inside the mothers stomach the baby is fed nutrients through a tube known as an umbilical cord.

The tube helps the child receive food and other important nutrients and also helps remove bad chemicals and waste from the child body so that it can grow up to be healthy and strong.

Once the child is born the mother will care for her child and nurse it by giving the baby milk.

She may continue to feed her child milk for the first 6 – 9 months of its life or until it is able to feed on its own and separate from its loving bond with its mother.

As the child develops and grows into a young adult it can repeat the process of its parents and give birth to its own child.

A healthy blue whale will usually reach maturity (the age when it can begin mating) between the ages of 5 – 10 and can live for up to 90 years.

10 Interesting blue whale facts for kids

  1. When fully grown a 180 ton blue whale can weigh as much as 24 adult elephants; in fact their tongue alone can weigh as much as an elephant. (elephants can weigh as much as 15,000 lbs!)
  2. Blue whales can consume up to 8,000 lbs or 4 tons of krill on a daily basis.
  3. A baby blue whale can consume up to 150 gallons of milk per day during its first year of birth.
  4. When in search of food the blue whale has been recorded diving deeper than 300 ft. and holding its breath for more than 35 minutes (most dives last 10 – 20 minutes or less).
  5. The blue whale isn’t truly blue in terms of color; it’s actually a grayish blue coloring that appears deep blue only after the whale dives under the water.
  6. When startled or threatened these marine mammals can reach speeds in excess of 30 mph for short bursts, however in most cases they manage an average speed of 3 – 12 mph.
  7. The only natural predator to the blue whale is a pack of hungry killer whales, however these attacks are fairly rare more often performed on young children and/or smaller blue whales rather than large adults.
  8. Because of their large size blue whales often travel alone or in small groups. Their large size provides these marine mammals with an excellent defense as their massive body deters most predators from attempting to attack them.
  9. During long migrations the blue whale is known to fast for as long as four months and live off of stored body fat that it accumulated during feeding season.
  10. Blue whales can communicate with one another from as far as 1,000 miles away due to their loud vocals and excellent hearing.