The blue whale is the largest animal on the planet, weighing as much as 200 tons! Even just its tongue can weigh the same as an elephant’s. It’s the largest animal known to have ever existed.

While they look blue underwater, and that’s how they got their name, blue whales are blue-grey.

Though the blue whale is the largest mammal in the world, they have a diet of krill, a tiny shrimp-like animal in the ocean. An adult blue whale can eat as much as four tons of krill daily.

They’re also a species of baleen whale. This means they have plates fringed with bristle, similar to your fingernail and called ‘baleen,’ attached to their upper jaw. The whales open their mouths wide to take in huge mouthfuls of seawater and push the water out with their tongue. Thousands of krill get stuck on the baleen, and the whale swallows it.

What is a blue whale’s habitat?

Blue whales live in all the world’s oceans. They’ve been found in tropical, subtropical, and temperate seas.

They migrate and travel across the world’s seas. In the summer, they tend to be in the cooler Arctic or Antarctic oceans, and then when it gets colder, they head to tropical waters near the equator for winter.

They might swim in small groups, but they’re often seen alone or in pairs. In areas with lots of food, however, there can be up to 60 whales at once.

How has the blue whale adapted to its habitat?

Besides its enormous size, the blue whale has adapted to its habitat in various ways. Here’s how:

  • Streamlined bodies

It can take a lot of strength to swim through the ocean’s powerful waves, so the blue whale has a long, streamlined body to help it move through the water. This allows it to swim more efficiently.

  • Flippers

The blue whale’s forelimbs are flippers that help with steering while swimming. This means the whale can ensure it’s heading in the right direction — especially helpful when you’re migrating to warmer waters!

  • Horizontal tails

The blue whale’s tail, called its ‘flukes,’ is positioned horizontally on its body. The flukes move up and down to propel the whale through the water. It’s an efficient way to swim around the world’s oceans.

  • Blubber

Like many other marine mammals, such as seals and dolphins, blue whales have a layer of thick fat. This keeps them warm in freezing temperatures, which is helpful if they’re swimming around in the Arctic or Antarctic seas. Fat also helps them to stay buoyant, so they float in water rather than sink.

  • Blowholes

Blue whales are mammals that live underwater — so how do they breathe? They do this with a blowhole. These can be sealed underwater and positioned on top of the whale’s head, so they can live before they even fully come up to the water’s surface.

  • No ears

While blue whales have a highly developed hearing but don’t have ears! Instead, they have an internal system of air sinuses and bones which detect sounds. Keeping things on the inside helps to reduce drag while swimming too.

What is the blue whale life cycle?

The lifecycle of a blue whale is in three main stages.

In terms of a blue whale’s productive life cycle, they can breed from around the age of seven and ten. Female blue whales breed every two to three years and give birth to one whale after up to a year of pregnancy. The babies are born around six to seven and a half meters long and rely on their mothers to survive. Baby blue whales are fed milk by their mothers for about seven to eight months after birth. They can drink up to between 22 and 90 kilograms of milk daily. Once the baby stops feeding from the mother and can hunt for food by itself, they leave and live alone for up to 90 years.

What do blue whales eat?

Blue whales sit at the top of the food chain and play an essential role in the marine environment’s overall health. Though gigantic, they feed on relatively small prey, primarily tiny shrimp-like animals called krill.

Blue whales act as a pump, ejecting the fish and zooplankton that they’ve eaten toward the surface of the oceans in the form of nitrogen-rich fecal matter. These nutrients are vital to the production of the marine ecosystem.


The development of technology in the 1900s led to the aggressive hunting of whales by whalers in pursuit of whale oil. This mass hunting nearly resulted in the extinction of blue whales, and although efforts have been made to increase their populations, their recovery has only been slight. As a result, they are federally listed as endangered and protected species.

Commercial whaling no longer threatens this magnificent species; however, climate change and its impact on krill, the blue whales’ major prey, makes them vulnerable.


Blue whales, particularly male blue whales, are quite the chatterboxes. But, unfortunately, they’re also the loudest species, too! Their calls can travel further than any other voice in the animal kingdom and reach 180 decibels – that’s as loud as a jet plane!

Both male and female blue whales produce several types of single-note calls, but only males sing. The purpose of their communication varies.

Some blue whale calls change with the seasons and the time of day, with single-note calls seeming to occur more often when whales return from deep dives. This type of call likely helps with pair bonding. Furthermore, individual calls are probably to animals nearby, whereas singing is an attempt to reach other whales further away.

Baby blue whales

  • are born at around six to seven and a half meters long;
  • weigh 3-4 tonnes when they’re born;
  • drink up to 90 kilograms of their mother’s milk per day;
  • leave their mothers at around six to seven months old;
  • can swim after about 30 minutes of being born;
  • have their mothers help them reach the surface to take their first breath.

Adolescent/mature blue whales

  • are mature by around five to eight years of age;
  • give birth to one new whale around every two to three years;
  • use their voices to attract mates;
  • are pregnant for around 12 months at a time;
  • rarely give birth to twins.

Adult blue whales

  • can live for up to 90 years, but usually around 70 to 80;
  • produce milk that can be up to 50% fat (female adult blue whales);
  • have a very strong bond with their calves (female adult blue whales);
  • teach their calves how to swim, breathe, and eat (female adult blue whales);
  • migrate to warmer waters to find mates;
  • find warmer waters to hunt for prey;
  • eat around 40 million krill per day, which are tiny crustaceans.

What’s the lifespan of a blue whale?

80-90 years.

Do blue whales find partners for life?


Some animals find a partner of the opposite sex to reproduce with for life, such as beavers, gibbons, and bald eagles. Blue whales have been observed to not mate for life. During the mating season, many whales gather together to find a partner to reproduce with. It has been found that some whales may come into contact with more than one other whale over the mating season in the space of one year.

Sometimes, male whales can fight one another when competing for a female to mate with. Males also go to great lengths to get the females’ attention during the mating season. Some may perform elaborate dances, others sing, and some charge at other whales to show their youth and strength. It is ingrained into the DNA of whales that producing offspring during the mating season is of the highest importance.

The breeding season usually occurs during the year’s colder months, so the feeding season can occur during the warmer months. This is especially true for species that hunt in the waters surrounding the Arctic or Antarctic.

Fun facts about blue whales

  • Blue whales communicate through songs. The voice of the blue whale is the loudest and deepest animal call on Earth.
  • Some blue whales have a yellow underside, leading to the nickname ‘sulfur bottom’ whales.
  • Its blood vessels are so big you could swim through them.
  • A baby blue whale (a calf) can weigh up to 2700 kg when born.
  • In good conditions, blue whales can hear and communicate with each other across distances of up to 1600 km.
  • They can grow over 33 meters — twice as long as a Tyrannosaurus rex! This makes them the largest mammal in the world.
  • They’re graceful swimmers and can dive as deep as 500 meters into ocean depths.
  • Blue whales have been protected from hunters since 1966.
  • Blue whales who have washed ashore will sometimes show affection to those who helped rescue them as if to say thank you.

Blue whale vocabulary

Adaptation – how living things are specialized to survive in their environment.

Baleen – bony, flexible strips in the upper jaws.

Blowhole – a whale nostril that is used for breathing.

Blubber – fat under the skin that keeps marine mammals warm.

Calf – a baby whale.

Diet – what whales eat.

Endangered – in danger of becoming extinct.

Fluke – the triangular tip of a whale’s tail.

Habitat – the natural environment of an animal or plant.

Krill – small, shrimp-like creatures.

Locomotion – the power to move from one location to another.

Mammal – warm-blooded, vertebrate animals with fur or skin.

Species – a group of living organisms with similar characteristics capable of breeding and exchanging genes.

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