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
Table Of Content
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.
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
Intelligence
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 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.
Habitat
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!