Dolphins: Characteristics, types, habitat, and more

Dolphins are  recognized , as one of the most intelligent animals in the world. Now let´s  learn about the main characteristics and wonders of these lovely creatures

The size of the dolphins ranges between 2 and 9 meters long.

We can find these cetacean animals near the coasts and  they are well known for their great interaction with humans.

The oceanic dolphins belong to the  Delphinidae  family, while  the families Platanistidae and Iniidae, contain both  the rivers  dolphins

Main Characteristics

In this article we will learn everything about these creatures, such as their  alimentation habits, reproduction and many other interesting things

The fusiform  anatomy of the dolphins  is  totally adapted to inhabit the water. Their sizes range  from two to nine meters long, and they can  swim really fast.

Dolphins have a caudal fin located in their  tails , which they employ   ​for propulsion. They also have some pectoral fins    which they employ to maintain the directional control of their swim.

The common dolphins are characterized by having  a gray skin, with  the lightest tones  on their  belly and  the darkest  ones on their  back. Some species also have lines or spots.Dolphins: dolphins anatomy

Another distinctive feature  of these creatures, is their capability to renew  their skin every two hours, which  allows them to move faster.

The snout of the dolphins is elongated , as well as their  jaws, which are made up of 20 to 50 teeth.

On the other hand, the dolphins have a single hole located on the top of the head,  known as  spiracle or blowhole; which they employ to breathe.

In relation to the brain, it can be said that it is large, and  its weight  ranges  between 1500 to 1600 grams compared to the human brain that only weighs about 1200 or 1300 grams.

The dolphins are one  of the most intelligent mammals,  due to the fact that they have a fairly   developed cerebral cortex, compared to the average of the rest of mammals.

A curious fact about this subject, is that when they are sleeping, one half of the brain remains awake, which allows  them to continue breathing. This results in them sleeping with one eye open, while the other remains closed.

On the other hand, in relation to the blood of this animal, it  can be said that it has an internal temperature of 36 degrees. This is because they are surrounded by a thick layer of fat under their skin, which  helps them withstand the low temperatures of the water in winter. Therefore, they tend to feed in greater quantity,  during this season.

As far as their senses,  they have a very acute and developed auditory sense, and their vision is much better, than what is expected for an animal that employs echolocation  to perceive their environment,   especially its colors , which they  perceive in limited way.

Their sense of smell few developed, could be mentioned as the only lack in this aspect.

Swimming Skills

The characteristics of their anatomies,   allow them to swim about 260 meters below the surface of the sea.  Although, they prefer to swim in shallow waters  in order to breathe from time to time.  They can stay under water  for about 15 minutes. It must be taken into account , that breathing is a totally voluntary process for dolphins, unlike humans. That is, it doesn´t represent a reflex as it happens with people.

In the same way it is important to emphasize,  that they can swim at  speeds which  range  from 5 to 12 kilometers per hour, even 32 km per hour in some occasions.

This depends on the species and the characteristics that it presents.

Unlike other animals, the movement commonly used for swimming is up and down.

It is important to note that the back portion of their  bodies, is more developed than the frontal muscles.

Dolphins  commonly employ their fins at sea,  to direct  their movements at the time of swimming.  In the same way they  use their tails , to provide most of the force they need in such movements.

In addition,  they have a sort of  horizontal fins in their tails,  which provide them better propulsion throughout the process.

They also possess dorsal fin like that of fish.

Let´s keep learning about this species

Communication And Vocalizations

Dolphins have the abilities to produce a variety of sounds, which are called  vocalizations . They employ the  nasal air sacs located under their   spiracles  to produce such sounds.

These   vocalizations can be classified into three categories. First of all, we find frequency modulated whistles, also the bursts of sound impulses, and finally the clicks, generally used for echolocation.

According to several specialists ,  dolphins also use these sounds to produce acoustic shocks to kill smaller prey.

As many of us know, every creature has features that allow it to communicate with its own species.

But in the case of the dolphins, they have complex system of signals and sounds. In addition to being a tool to reproduce and hunt, the sounds they emit also work to guide them in relation to the environment.

This is because the alterations in the frequencies can warn them,  if they are close to some kind of obstacles.

In the same order of ideas,  every dolphin in the sea has an unique whistle. This differentiates it from the rest.

Dolphins are also characterized by living in herds, which in  most cases reach the amount of 1000 animal.  For this reason this type of communication is efficient.

In this way they can recognize each other, and develop some kind of communication together.

Besides the communication based on vocalizations,  dolphins recurrently produce dances and jumps  also for purposes of communications.

Dolphins are also characterized  by keeping  in touch with the other members of their groups, and most of the activities they carry out are performed in such way. This is reflected in different stages  of their lives.

To obtain food they maintain teamwork strategies, that allow them to obtain better results.

They also tend to  form groups  to take care of the mother and the offspring,  in the case of childbirth. ,

Even if a dolphin is dying, the other members of its herd, help it to stand on the surface and breathe more easily.

Here we go, with more information about these sounds


In terms of intelligence, the most interesting  aspect is given by the fact, that dolphins are even more intelligent than human beings.

For example, the cortex which is the most recent portion of the brain in terms of evolution, and is also the area  where the conscience is produced,  it is much more complex  in the case of  dolphins than in human beings. Therefore, this statement leads researchers to conclude,  that the intelligence of dolphins is superior to that  of human beings.

But in a different way.

Dolphins are able to use all the possibilities offered by the environment in which they live, but without changing or altering its order.

The different studies based on the intelligence of the dolphin, have demonstrated  that there is a great similarity with humans.

These studies are supported by a rigorous anatomical research, where it is demonstrated that the brains of the dolphins present  many characteristics that can be associated with a high degree of intelligence. The scientists have discovered , that the cerebral cortex in dolphins have the same spreads as in the case of humans.

Dolphins are mammals with a fairly developed intelligence, very similar to that of humans.

Reproduction  Methods of the Dolphins

The copulation act of the dolphins is  usually short, and it is repeated more than once in a short time.  The process begins when the male intones vocalizations, that is, whistles to attract the female in order to reproduce. It is known that the dolphin is the only animal, apart from the man, that carries out sexual relations in order to experience pleasure.

The gestation period varies according to the species,  from 11 to 17 months. Dolphins have only one offspring each time, twins are no common .

Their sexual activity begins at an early age, even before they reach  the sexual maturity, this also varies according to the species. Their genital organs are  found internally, unlike most mammals.

According to studies that have been carried out with dolphins in captivity, It has been concluded that dolphins mate mainly in spring time. It is also known that a male dolphin can mate multiple times in an hour, usually with the same female,.

The birth of a dolphin can happen anywhere, and the herd usually surrounds the mother in  that moment,  to avoid the threat of any predator such as sharks;  which are usually attracted by the fluids and blood that results in labor.

After the female has her offspring, she needs help from the herd to take care of  It. For this reason they keep swimming together with the group, unlike the male that sometimes tends to get away while swimming.

Alimentation Habits  Of  Dolphins

The first thing to know about the alimentation  habits of the dolphins, is that they are totally carnivorous animals.  In general, the amount of food they consume is a proportion that is considered  between 4 and 9% of their body weight every day

In turn, the just born  dolphin feeds on breast milk  during  a period of about 18 months. Then, it feeds on fish, squids or crustacean.

The dolphins swallow their whole prey  without chewing it,  employing the muscles that are located on the back part of the tongue. Then they use the throat to expel the salt water,  in order to take total advantage of the food It is known that adult dolphins have the capacity to ingest fish weighing up to 5 kilograms.dolphins: mother and calves

Dolphins use different hunting methods to search for their food. In most cases they hunt using their speed but  they also have  the ability to use echolocation, in order to find prey that are buried in the sand.

The echolocation is such an useful tool,  that soldiers from different countries use this ability to find underwater objects. The echolocation helps dolphins find,  different types of materials in the sea such as rubber, plastic, wax or metal.

They can even distinguish between copper and brass, by perceiving   the type of sound that materials make when they come into contact with water.

Dolphins are also  known for hunting fish that are  grouped in herds.  This tactic is based on corralling  them, so that one  individual separates from the rest of the group.

This technique can be also employed on the shores of the sea, to take advantage of the waves and capture them more easily, but  sometimes this technique can be also risky for them.

The fish they consume vary depending on the species of dolphin. For example  the orcas  , which are are part of the family Delphinidae, has a wide range of tactics and methods of hunting since they consume different types of fish.

It is also important to point out,  that dolphins usually eat more  during the winter,  since they need much more fat to withstand the low temperatures of the water.

 Hunting Strategies

In most cases the dolphins must resort   to teamwork in a  coordinated way.  Following, the group of dolphins approach and surround a school of fish, in order to group them as compact as possible. When this happens, the dolphins take turns so that each one can feed on the fish that are trapped between them, while the  other dolphins, keep the fish surrounded during all this time.

On the other hand, the other method that  is also employed  by these creatures , is to corral the prey in shallow waters, until they get trapped in the coast,  being captured by the dolphins that take turns to eat them

Types of  Dolphins

First of all, we must know that all dolphins belong to the family of cetaceans, which also  includes whales,  and porpoises. In turn, the cetaceans are divided into sub-groups,  comprised by a wide range of animals.

As far as   the dolphins, we should start mentioning that there are river dolphins,  which belong to the family  Platanistidae. They inhabit in  the Ganges River, the Indus River, the Amazon River, the Chino River and finally those of the La Plata River

On the other hand , we find the marine  dolphins, that belong to the family Delphinidae, comprised by  the following species: Risso dolphin, white faced dolphin, dark dolphin, common dolphin, Peale dolphin, Pygmy killer whales, white-bellied dolphins, pilot whales, false killer whales, broad-billed dolphins , the right whale dolphins of the north, the bottlenose dolphin, among others. These species are usually the best known because they interact with humans.

Most Common Species

Although there are many more families; and therefore much more sub-groups, the species mentioned above are usually the most common.

In general there are 32 species of sea dolphins; and about 5 species of river dolphins,  being the orca the  most highlighting one.  This specimen can grow up to more than 6 meters long,  which makes many people think  that it is a whale , although it has the typical characteristics of a dolphin. The orca is also found in the classification and characteristics of carnivorous marine animals.

On the other hand, one of the best known worldwide is the bottlenose dolphin, which is the one  that appear in television series and shows.

This specimen can grow  about 2, 5 meters even up to 2,8.


Dolphins inhabit in almost any part of the world, especially in those  places where they can find water and food.

Therefore we can find dolphins in all the seas of the world,  except for the Caspian Sea and the Aral Sea. On the other hand the dolphins, in relation to other mammals breathe air instead of water, thus they have lungs instead of gills. That is why  unlike most fish,  dolphins  tend to inhabit on the surface of the ocean.

So, there is not a specific habitat for the dolphins; since they look for places  where the species they feed on are available.

As we mentioned before dolphins tend to live in herds, so that they can defend themselves if they are facing a possible attack, and to ensure success in hunting strategies. As a result  they are quite sociable   creatures.

What can be taken for granted,  is that the dolphins will take as their habitat the areas where there are more prey. Therefore, if the fish are scarce the dolphins will consequently migrate to waters where it is easier to get their food.

More specific distribution

To talk about a more specific habitat, we could mention the tropical waters. The Atlantic, Pacific and Indian Oceans and their respective seas, are the most common locations for these creatures.

The bottlenose dolphin   which is the most common one,  can  be found  it in the Pacific Ocean, in much of the territory of Japan and Australia, also in the southern United States, including Chile and Hawaii.

This well-known species also inhabits the territory of North America and South Africa. On the other hand, the species of river dolphins,  are distributed mainly in the Amazon, also in the Ganges, also in the Yangtze, and even in the River Plate and the Indus River.

Main Threats

The captivity can be mentioned as the main threat of this species.

It is known that 95% of dolphin deaths are attributed to their catch,  to keep them in aquariums and research facilities.

During this process, the dolphins besides the suffering  that entails being taken away  from their natural environment, are exposed to the dangers  that represent  their capture and transport.

On the other hand,   the increase in  the chemical pollution  of their environment, can be mentioned as another important threat.

Therefore the pollution caused by oil, chemicals or metals means a great risk that has its impacts on the habitat where the dolphins develop.

The effects of this pollution affects  the dolphins at early ages, causing terrible diseases  and their death.

Moreover,   dolphins  are more likely to become contaminated; because their position is at the top of the food chain. Therefore, when they eat a fish that is already contaminated, they also suffer the consequences.

Another reason why dolphin species are in danger of extinction is noise pollution, which causes negative impacts on their natural habitat.

As we already know,  these animals have a great sense of hearing; so they are more sensitive to any noise. Then the processes of oil extraction, or the radars that are used in the navigation and even the engines of some ships,  generate  currents of underwater noise, that usually frighten or disorient the dolphins. The damage is unavoidable, since they are quite sensitive to this type of noise.

Many of these marine animals  tend to migrate from  the higher latitudes;  directing their trip to the south while the winter lasts.

Can we preserve Our Marine Species?, of course we can… so, let´s learn how!


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