Blue Whales: Characteristics, threats and more, about the biggest creature ever

The blue whales are the biggest creatures in the world, they are also known as Balaenoptera Musculus.  This species belongs to the family of the Balaenopteridae, and they are the largest animals that have ever existed.

Blue whales used to inhabit   in different oceans, until the 20th century; when the ruthless hunting made of them an endangered species. This fact  alerted  the international communities, so the required measures were taken in order to protect them  ..

In spite of being the  biggest creature in the world,  its contexture is not that robust.  Contrary,  the blue whale is rather thin, but its weight  is evenly distributed throughout its body;  which makes of it, an agile swimmer.

This stunning creature, which highlights because of its size and  powerful aspect, is one of the most lovely marine animals.  Thus we invite you to know everything about it.

Characteristics Of The Blue Whales:

The blue whales,  are characterized by having an elongated body and a wide head. They have two holes ( spiracles) on their back, that help them breathe with ease .

These  specimens , (unlike the Beluga or White Whale), have  beards instead of teeth,  which are similar to the bristles of a toothbrush, and help themcapture their small preys.  It’ s an interesting fact, that in spite of being the largest animal in the world they feed on small species.

Under the water the blue whale presents an intense color, but when they emerge to the surface; their color  changes to bluish gray.

Their belly has yellowish shades, due to the large amounts of microorganisms that adhere to them. They have a broad, flat head that does not match their stylized body.

Following , we list others interesting characteristics of the Blue whales.

    • They have a large tongue, of an estimated weigh of 7 tons
    • They can store about 90 tons of water in their jaw as well as the same amount of food,
    • Their heart weighs around 600kg.
    • Despite their large size, blue whales can reach speeds of up to 50km / h when they are threatened. However their average speed is around 22 km / h , or even lower when they are looking for food.
    • Blue whales can submerge up to 500
    • They can stay underwater, for periods of time that vary between 10 and 20 minutes emerging then to the surface in order to breathe.
    • , They can store up to 5000 liters of water in their lungs
    • Their bones are quite big, due to their size;  and help them support their anatomy.

Blue Whales have a fin , which helps them move within  the water.

But let´s start learning more about this wonderful creature….


These specimens have a variable size, which depends on the sex, age and type, among other aspects. The female can reach up to  27 meters in length, while males can reach between 20 to 24 meters although  there are individuals of up to 30 meters in length.

The blue whales  have long fins, of  an average height   between 10 to 13 inches which  help them move at a high speed, in spite of being so large.

blue whales: measures


This majestic animal can reach up to 180 tons in weight.  Its tongue can weigh as much as an elephant,  and its heart is heavier than a common car.  This is due to its size and the big amounts of food she eats  every day.


There are different opinions about the taxonomy of the Blue Whales. Most specialist agree, that these creatures, as well as beluga whales , belong to the family of the balaenidae, so they call them fin whales.

In this sense, the blue whales are  usually classified, as one of the 8 species of fin whales that are already included in the genus balaenoptera. However, there are specialist who think, that blue whales belong to a separated genera.

There are cases where it has been documented, that this whale is more related to the gray whale ,  and other individuals of this species, than to the white whale . If this is confirmed, another subspecies of them should be reconsidered.

The name musculus of the blue whale, comes from the Latin and means muscular. The scientist Linnaeus was the one who gave this name to the blue whale.

However  many people think it was a bit ironic and double meaning to denominate it this way, because it was formerly called with another series of name like rorcual of Sibbald in honor to Sir Rober Sibbald, great blue whale and great rorcual of the north. These denominations are not used anymore.

The Blue Whale´s  evolution has changed over the years,  and it will go on, so we cannot lose sight of it.

Subspecies of the Blue Whale.

B.m Musculus Linnaeus.  Northern blue whale, which includes the populations of the Atlantic and North Pacific.

B.m Musculus Burmeister. Antarctic blue whale,  which is the largest specimen, and inhabit in the Antarctic Ocean.

B.m Brevicauda. blue pygmy whale, which  main populations, are located in the Indian Ocean and Southern Pacific.

B.m Indica. This the most controversial specimen, since it resembles the previous subspecies, but they are located in the Indian Ocean, and they are named as big fin whale of India.

Communication Methods of the Blue Whales

Blue whales emit very powerful and regular sounds under water, especially for their long range communication.  Most scientists affirm, that the volume of these sounds varies between 155 and 188 decibels

Moreover,  when blue whales are gathered  in groups, they communicate by emitting sounds of very low frequency, which are almost  imperceptible for humans. These sounds last  around 30 seconds.

The reason why they emit these low sounds is still completely unknown, although there are 5 possible reasons ( which are listed below),  according to different studies;

    • To maintain the individual distance,
    • For species recognition,
    • Transmission of information regarding food or possible threats
    • To indicate their location,
    • To indicate the stable position of a prey

Finally, it´s important to know, that the  communication increases during the breeding season. During this period,  males tend to emit these sounds in order to court  the females. Many specialists believe, that this type of sounds  also serve as a kind of warning, to keep away other males.

Believe it or not, these are the wonderful sounds they emit…

Blue Whales: Habitat and Distribution.

We can find the blue whales in all the oceans of the world. Their distribution varies according to the time of the year; during the polar summers they move to these waters  looking for big amounts of food, and

In the winter they move to warmer waters, to be able to mate

And give birth  their offspring.
Blue whales are commonly   found in pairs, although they can also remain in small groups or alone.
It is said that the blue whales are cosmopolitan individuals, since they are scattered  in all the oceans of the world, except the Arctic, and   the Mediterranean and ojotsk seas.

Blue whales mostly inhabit,  in continental shelves and in different types of open ice fields, although they have also been seen in deep seas. Nowadays, the biggest population of blue whales in the world, is located the Pacific North.


The current population of blue whales is estimated  between 10,000 and 25,000.  However, at the beginning of the 20th century they were on the verge of extinction,  due to the intensive hunting that the whalers carried out to obtain their oil.

Between 1900 and the mid-1960s, around 360,000 blue whales were exterminated. Finally, in 1966 the International Whaling Commission determined their protection, but since then the situation has only slightly improved.   The statistics regarding  their population, vary according to the areas where they are located.

The blue whales are classified as an endangered species, according to the IUCN, ( International Union of Conservation of Nature). The specimens that inhabit in the Antarctic, have the worst condition, so they are included in the red list of the referred association.

The largest known concentration of this species, with at least 2000 individuals, is the one located in the north-east pacific.

They  are called northern blue whales, and they are distributed from Alaska to Costa Rica; even in California, during the summer.

The migratory routes of these species are not completely known   yet.  There are evidences of their presence in the northern Indian Ocean; where it is speculated that they have a stable population. On the other hand, there are evidences of blue whales that have been found in Chile and Peru, which can also be part of a different population.

Some Antarctic blue whales, usually approach to the east coast of the Atlantic in winter, and occasionally to the north of Western Australia.

Many efforts have been made to calculate the total number of specimens that exist. Several universities have taken this task, in order to determine  the true statistic of these mammals.

The Blue Whales’ Common Behavior

In general the blue whales tend to be  more solitaries than the dolphins. They commonly live alone or in pairs, even sometimes forming small groups of 7 individuals . In few occasions,  they have formed groups of up to 60 individuals,  but this occurs when they find big amounts of food.

They can only stay underwater for about 20 minutes,  before surfacing for air. As a result, they are very often observed by those interested in the largest animal in the world.

In addition, according to several studies; it has been demonstrated that they mostly live in pairs which remain together for a long time.

Although, there also cases of  males, which pair with different females at different times;  but this is not  very common.

It is believed that most Blue Whales migrate between tropical waters and polar waters. In general, in the winter season they move towards tropical waters of low latitudes, to reproduce and give birth their offspring .

In summer, they migrate to colder polar waters of high latitudes, for feeding purposes. It is also believed, that  during their  migration, and when they stay in reproductive areas  blue whales practically do not feed for at least 4 months, living off the energy stored in their body reserves.

However,  recent studies have   revealed  that Blue Whales in the Costa Rica Dome feed themselves actively in the winter breeding areas.

Moreover, most of the populations of blue whales are migratory: they spend the winter in warmer waters of low latitudes, and in the spring they take course to the cold waters near the northern and southern hemispheres; they spend the summer feeding at high latitudes and in the autumn they return to warm areas. Only few populations prefer not to migrateWhat

The Blue Whales’ Alimentation Habits

The diet of the blue whales is based mainly on Krill, consuming up to 40 million of these crustaceans only in 1 day. Once they close their jaw, they  eliminate the excess of water that they have ingested, retaining only the food.   There may be other species that are accidentally devoured by this cetacean, such as small fish, squid and other crustaceans.

They always feed in the areas,  with the highest concentration of krill. The energy intake requirements of an adult are around 1.5 million calories each day.

They usually feed at depths of more than 100 meters during the day, and only feed on the surface at night.

The submersions during their feeding time, last between five and fifteen minutes, although dives of up to twenty minutes can be carried out,  and there are records of up to thirty-six minutes long.

The feeding of the blue whale is carried out  by a filtering system; they open  their mouth, introducing  big amounts  of water and krills. Then they close  their jaw,  pushing  the water back out through their .beards

This system allows the water comes out, while capturingonle  the preys.  Although their diet is based almost exclusively on  krill, incidentally  they also consume small fishes, crustaceans and squid that swim among it.

What do the blue whale calves eat?

The offspring of the blue whale, after being formed and born, requires at least 100 or 150 liters of breast milk per hour; which will prepare it for becoming  a big krill predator, in the long time.


Let’s watch this illustrative video

How do Blue Whales Reproduce?

The reproductive capacity of these cetaceans is relatively low, in comparison with other mammals as for example the beluga white whale.

The gestation period varies between 9 and 16 months, giving birth only one offspring. In addition, 3 years must pass for the female, to have another offspring.

The baby whales are commonly called calves, they weigh around 2 tons and measure between 4 or 5 meters in length. They also  have the ability to swim, since the beginning of their lives

The mating can occur at any time of the year, but summer tend to be the most common season for this purpose.

Scientists agree that before thecopulation, the whales have a certain previous game ,that consists of friction increasingly stronger.

The sense of smell  the blue whales, is not well developed, so the male can not easily smell the female when she is in heat; but she has specific tactics  to let him know.

The offspring  grow very fast, approximately 3 centimeters per day, during the first two months of their lives. In part, this is because whale´s milk is very nutritious, and has a high percentage of fat.

They spend between seven and twelve months, drinking milk from their mother. This process of breastfeeding their  babies whales, is not unconscious, unlike human beings.

The young whales accompany their parents in the migratory movements, and the whole group takes care of them. The physical contact between the whales and their offspring  is a constant, at the beginning of their lives.Whales reach sexual maturity, between six and thirteen years of age.

Due to different external factors , such as hunting and others risks; the age of sexual maturity has been advanced, since young whales have a faster growth by having to replace their parents.

The age that a whale can reach,  depends on its physical conditions, the species and others external factors such as the actions of the human beings.

The females come into heat several times during the year. We can distinguish two types of copulation. In the first one , the male member enters half into the vagina of the female, this act doesn´t last more than ten seconds. In the second type of copulation, the male´s member is fully introduced;  and it usually lasts thirty seconds.

Conservation Of  The  Blue Whales.

At the beginning of the 20th century, blue whales were on the verge of extinction due to the intensive hunting,  that the whale hunters carried out, to obtain their oil. Between the 1900s and the mid-1960s, about 360,000 blue whales were exterminated.

As a result in 1966,  the International Whaling Commission, developed  the necessaries measures, to ensure their protection. However this situation has only slightly improved over the years.

Blue whales have few predators, although it is known that they suffer attacks by sharks and orcas; and many of them die or are injured when they hit large ships.

Today, blue whales are classified as one of the endangered species  ( see article endandegered whales) by  the Red List of the Union for World Conservation. There is an estimated quantity  of 12,000 individuals.

However, some experts believe that there may be more of them in the ocean. This is due to some possible sightings throughout the Arctic region, where they were once very common.

The great advantage of the blue whale, is that it can live a very long life, up to 80 years;  according to several  studies.

 Blue Whales: Main Threats

The indiscriminate  hunting  of these creatures, in countries such as Japan, Iceland and Norway, must be listed as their main threat.

There also others factors such as climate change, pollution of the sea; lack of food by overfishing and accidental captures  that injure or kill them.

The International Whaling Commission has the function of regulating whaling;  but has not made significant progress, due to the great economic interests that are involved .

In spite the demand of meat and whale products has decreased,many countries subsidize fishing activity , so  the amount of captures does not lower.

Under the excuse of hunting for scientific purposes , hundreds of whales are killed worldwide.

Many times they are moved from their territories, to places without hunting prohibitions, helped by the complicity of countries that receive retribution in return.

In addition, they take advantage of the few international controls that often violate existing regulations.

There are many countries that want to protect the whales, but they have not been able to counteract the pressures  of the hunter countries, which have great economic power. Greater international social pressure is needed to take measures to save the whales, such as:

    • the creation of sanctuaries and safe routes for the migration of whales, strict quotas for hunting,
    • In severe cases the total prohibition of hunting should be considered,  until the total recovery of their population.

Human Beings as a Threat.

Besides the hunting of blue whales by humans, which as we have already mentioned, is the main threat for these creatures, there are also others interactions that must be considered;

    • They are often injured, sometimes fatally,  by collisions with large vessels on the high seas
    • They sometimes get entangled in fishing nets.
    • The environmental noise, produced by the humans in the ocean, including the sonar; drowns the vocalizations produced by the cetaceans, hindering their communication.


    • Human threats to the potential recovery of  the blue whales´population, also include the accumulation of PCBs  (polychlorinated biphenyls) , and other chemicals that they eat while feeding.  These chemical are obviously transmitted,  to their offspring through breast milk.

Global Warming.

Global warming causes glaciers to melt rapidly, which leads to a large increase in the amount of fresh water in the oceans. There is a risk of reaching a critical point in that increment, which could disturb  the circulation of these whales .

Like most known cetaceans, blue whales are highly migratory and spend the summer in higher, colder latitudes, where they feed in waters with an abundance of krill.

In winter they move to lower latitudes, warmer, where they mate and give birth.

Since their migratory models are based on the temperature of the ocean, a change in this circulation, that displaces hot and cold water around the world, would probably have an effect on their migration.

A change in ocean temperature would also affect their food supply, since warming would cause a decrease in salinity levels, that would lead to a significant change in the situation and abundance of krill.

Blue Whales´ Predators .

The orca is the only known animal under the sea, that usually attacks the blue whales. However given their big size, the orca prefers to confront the small calves, or the adult and sick whales.

There are documented reports of attacks against blue whales, carried out by Orcas.  These reports showed, that in the Pacific Ocean no less than 25% of adult specimens had scars resulting from orca´s attacks .

There was also  a death specimen in the Baja California area, that was presumed to be the victim of an Orca.

However, although it’ is shown that orcas attack and can even kill a blue whale, the death rate due to these attacks is unknown.

Finally we leave this video for you , with more information about the sounds of these whales…

Deja un comentario