Blue whale facts for kids
Quick facts for kids Blue whale |
|
|---|---|
 |
|
|
Adult blue whale
(Balaenoptera musculus) |
|
 |
|
|
Size compared to an average human
|
|
| Conservation status | |
| Scientific classification | |
| Genus: |
Balaenoptera
|
| Species: |
musculus
|
| Subspecies | |
|
|
 |
|
| Blue whale range (in blue) | |
| Synonyms | |
|
|
The blue whale (Balaenoptera musculus) is the largest animal on Earth, both today and in all known history! These amazing marine mammals are a type of baleen whale. They can grow up to 30.5 meters (about 100 feet) long and weigh as much as 200 tons. Blue whales have long, slender bodies that are usually grayish-blue on top and a bit lighter underneath.
There are four main types, or subspecies, of blue whales found in different parts of the world's oceans. These include populations in the North Atlantic, North Pacific, Southern Ocean, and Indian Ocean. Some scientists think there might even be a fifth type living off the coast of Chile.
Blue whales usually travel long distances. They move from their summer feeding areas near the North and South Poles to warmer waters near the equator in winter to have their babies. They are filter feeders, meaning they eat tiny ocean creatures called krill. Blue whales usually live alone or in small groups. They make very loud, low-frequency sounds to communicate. The only natural predator of a blue whale is the orca, also known as the killer whale.
Sadly, blue whales were hunted a lot in the past, almost to the point of disappearing forever. Luckily, hunting them was banned worldwide in 1966. Today, they are still considered an Endangered species. They face dangers like being hit by ships, ocean pollution, loud underwater noise, and climate change.
Contents
Discovering the Blue Whale
How Blue Whales Got Their Name
The scientific name for the blue whale, Balaenoptera musculus, has an interesting story. Balaenoptera means "winged whale." The word musculus can mean "muscle" or a tiny "mouse." Some people think Carl Linnaeus, who named the species in 1758, might have been making a joke about how such a giant animal could have a name meaning "mouse"!
The common name "blue whale" comes from the Norwegian word blåhval. This name was used after a special harpoon gun was invented, making it easier to hunt these huge whales. Whalers sometimes called them "sulphur bottom" whales. This was because their bellies could look yellowish from tiny plants called diatoms that grew on their skin.
Blue Whale Family Tree
Blue whales belong to a group of whales called rorquals. Scientists believe that the rorqual family started to appear between 5 and 10 million years ago. The oldest blue whale fossil found is about 1.5 million years old.
Sometimes, blue whales can interbreed with fin whales. This means they can have babies together, even though they are different species. Scientists have found evidence of these mixed-species whales in different oceans.
Where Blue Whales Live
Blue whales live in oceans all over the world. However, you won't find them in the very cold Arctic Ocean or in smaller seas like the Mediterranean or Bering Sea.
There are different groups of blue whales, often called subspecies or populations:
- Northern Blue Whales (B. m. musculus): These live in the North Atlantic and North Pacific. They are often seen off the coasts of Canada, the U.S. (like California), and near Iceland. They travel south to warmer waters for winter.
- Northern Indian Ocean Blue Whales (B. m. indica): These whales live year-round in the northwestern Indian Ocean.
- Pygmy Blue Whales (B. m. brevicauda): These are found in the Indian Ocean and South Pacific. They are a bit smaller than other blue whales. You can find them near Madagascar, Australia, and New Zealand.
- Antarctic Blue Whales (B. m. intermedia): These are the largest blue whales and live around Antarctica. They travel north to warmer areas during certain times of the year.
Scientists are also studying blue whales off the coast of Chile. They might be a unique group, possibly even a new subspecies!
Blue Whale Description
Blue whales have a sleek body with a broad, U-shaped head. Their flippers are long and thin. They have a small, curved fin on their back, close to their tail. Their tail, called a fluke, is very wide and thin.
Inside their upper jaw, they have many black plates called baleen. These plates act like a giant filter. Their throat has many grooves that stretch out when they eat. Blue whales have two blowholes on top of their head. When they breathe out, they can shoot water and air up to 12 meters (40 feet) high! Their skin is a mottled grayish-blue, which helps them blend in underwater.
Blue Whale Size
The blue whale is truly the largest animal known to have ever lived. Imagine an animal longer than three school buses! The longest blue whale ever measured was about 30.5 meters (100 feet) long. Female blue whales are usually a bit larger than males.
An adult blue whale can weigh between 72 and 135 tons, but some can reach up to 200 tons. Their skull can be almost 6 meters (19 feet) long.
Blue Whale Life Span
Blue whales can live for a very long time, usually around 80 to 90 years, or even more! Scientists can tell a whale's age by looking at its earwax. Each year, a new layer of wax forms, like rings on a tree. The oldest blue whale found using this method was estimated to be 110 years old.
Blue Whale Behavior and Ecology
Blue whales are usually solitary animals, meaning they prefer to be alone. Sometimes, you might see them in pairs. If there's a lot of food, more than 50 blue whales might gather in one area.
Many blue whales go on long migrations. They travel to cold waters near the poles in summer to feed. Then, they head to warmer waters near the equator in winter to have their calves. They seem to remember the best places to find food. Some whales might stay in one area all year, or only certain age groups might migrate.
Blue whales usually swim slowly, about 2 to 8 kilometers per hour (1 to 5 miles per hour). But if they need to, they can swim much faster, up to 48 kilometers per hour (30 miles per hour)! Because of their huge size, it's rare to see them jump completely out of the water.
Blue whales can dive very deep. The deepest dive recorded was about 315 meters (1,033 feet). Their heart rate can slow down to just 2 beats per minute when they are deep underwater.
Diet and Feeding
Blue whales eat almost nothing but krill. Krill are tiny, shrimp-like creatures that live in the ocean. To eat, blue whales use a method called lunge feeding. They swim very fast with their mouths wide open, scooping up huge amounts of water and krill. They can take in about 220 tons of water at once!
Then, they use their large tongue to push the water out through their baleen plates. The krill get trapped inside, and the whale swallows them. Blue whales need to eat a lot of krill to get enough energy. An average blue whale eats about 4 tons of krill every day!
Different blue whale populations eat different types of krill. For example, in the Southern Ocean, they eat Antarctic krill. In California, they mostly eat another type called Thysanoessa spinifera. Interestingly, blue whales in the Northern Indian Ocean also eat small shrimp and sometimes even fish or jellyfish.
Reproduction and Life Cycle
Blue whales usually become adults and can have babies when they are between 5 and 15 years old. Females are typically ready to reproduce around 10 years old, and males around 12 years old.
Not much is known about how blue whales find partners or where they have their babies. Males often try to attract females and may compete with other males. Blue whales usually mate from fall to winter.
A pregnant female blue whale eats a lot, about four percent of her body weight every day, to support her growing baby. The baby whale, called a calf, stays inside its mother for 10 to 12 months. When a calf is born, it's already huge, about 6 to 7 meters (20 to 23 feet) long and weighing 2 to 3 tons!
Blue whale mothers produce a lot of milk, up to 320 kilograms (700 pounds) per day. Calves drink this milk and grow incredibly fast, gaining about 90 kilograms (200 pounds) every day! They are usually weaned, meaning they stop drinking milk, when they are 6 to 8 months old. A mother blue whale usually has a new calf every two to three years.
Blue Whale Vocalizations
Blue whales make some of the loudest and lowest sounds of any animal on Earth. Their calls are so low that humans can barely hear them. These sounds can travel for hundreds of miles underwater! The main sounds they make are between 8 and 25 Hz.
Blue whale songs are different depending on where the whales live. For example, blue whales in the Eastern North Pacific make pulsed calls and tonal calls. These songs are usually sung by males, which suggests they might be used to attract mates. Other calls are used by both males and females when they are feeding or socializing.
Scientists have noticed that some blue whale songs have become lower in pitch over time. This might be because as blue whale populations recover, males are singing at lower frequencies to show they are larger and stronger.
Blue Whale Predators
The only known natural predator of blue whales is the orca, also called the killer whale. While orcas are powerful hunters, attacks on adult blue whales are rare. However, orcas sometimes target blue whale calves.
Scientists have seen many blue whales with scars that look like rake marks, which are signs of past encounters with orcas. There have been a few documented cases of orcas chasing and attacking blue whales, especially calves.
Health Threats to Blue Whales
Blue whales can sometimes have small creatures living on or inside them. For example, tiny plants called diatoms can grow on their skin. Barnacles, which are small crustaceans, can also attach to their skin. They can also have tiny parasites, like worms, living inside their intestines. These are generally not a major threat to the whale's health.
Protecting Blue Whales
The global population of blue whales is much smaller than it used to be. In 1926, there were at least 140,000 mature blue whales.
Because of their low numbers, blue whales are classified as endangered. This means they are at high risk of becoming extinct. They are protected by laws and international agreements around the world. For example, the International Whaling Commission banned all blue whale hunting in 1966.
Dangers Blue Whales Face
Blue whales were hunted heavily in the past. In the mid-19th century, new harpoon technology made it easier to catch these fast, giant whales. Between 1930 and 1931 alone, about 30,000 blue whales were killed. In the first half of the 20th century, over 350,000 blue whales were hunted in the Antarctic. This hunting pushed them almost to extinction.
Even though hunting is banned, blue whales still face many dangers today:
- Ship Strikes: One of the biggest threats is being hit by large ships. This is especially a problem in busy shipping lanes, like off the coast of California or Sri Lanka. Scientists are working on ways to reduce these collisions, such as changing shipping routes or slowing down vessels.
- Ocean Noise: Loud noises from commercial ships and oil and gas exploration can disturb blue whales. These noises can make it harder for whales to communicate, find food, or even rest.
- Pollution: While blue whales eat low on the food chain, they can still be affected by pollutants in the ocean. Studies have found chemicals like pesticides and flame retardants in their bodies. These chemicals can be passed from mother whales to their calves.
- Fishing Gear: Sometimes, blue whales can get tangled in commercial fishing nets or traps. This can injure them or prevent them from swimming and feeding properly.
Scientists and conservationists are working hard to understand and protect blue whales. By reducing these threats, we can help these magnificent giants recover and thrive in our oceans.
Fun Facts about Blue Whales
- Today, there are estimated to be between 10,000 and 25,000 blue whales in total worldwide.
- When a baby blue whale, called a calf, is born, it's already about 7 to 8 meters (23 to 26 feet) long and weighs around 2 to 3 tons (4,000 to 6,000 pounds).
- Blue whales can dive to depths of about 500 meters (1,640 feet) and hold their breath for up to 30 minutes.
- Scientists estimate that blue whales can live for 80 to 90 years, and some might even live for over 100 years!
- While they appear blue underwater, their skin is actually a mottled (patchy) bluish-grey color. When seen through the water from above, or when they are at the surface, their skin can look a beautiful bright blue.
- They produce very low-frequency sounds, often called "songs," that are louder than a jet engine! These sounds can reach up to 188 decibels, making them the loudest animal on Earth. For comparison, a rock concert is usually around 120 decibels.
- A single blue whale can eat up to 4 tons (about 8,000 pounds) of krill every single day during feeding season.
- They can weigh up to 200 tons (about 400,000 pounds). To give you an idea, that's as heavy as about 30 adult elephants!
- Their heart alone is the size of a small car, and it beats only about 8-10 times per minute when they're diving deep.
- Their tongue is so massive it can weigh as much as an elephant, which is around 4 tons!
See also
In Spanish: Ballena azul para niños
- Largest organisms
- List of cetaceans
- List of largest mammals
- List of whale vocalizations
