The dolphin for kids

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Egbert Haynes
The dolphin for kids

Dolphins are highly intelligent, curious, funny and interesting aquatic animals. There are about 40 species of dolphins on our planet, and although there are some freshwater dolphins in South America, most of the dolphins are saltwater, that is, they live in the seas and oceans around the world, from warm waters equatorial to cold subpolar waters.

The best known species of dolphins are bottlenose dolphins and killer whales, also known as killer whales… That's right, these animals belong to the same family as dolphins!!!

Dolphins are aquatic animals

Are dolphins fish?

Although they live in water and have fins like fish, dolphins belong to the group of mammals, as well as whales and sperm whales, for example, or like dogs, cats, cows, rabbits and you! same!

That they are mammalian animals means that they are warm-blooded, that they feed their young with milk, that they must rise to the surface of the sea to breathe air and that they have hair..

They have hair?

That's how it is. Adult dolphins do not have it: their skin is smooth, rubbery and slippery, which helps them a lot to swim at impressive speeds, to jump very high over the water and to reach great depths.

However, their young, when they are born, have a little hair around their face, but it falls off after a short time, without leaving any trace..

How do they breathe?

Hole where dolphins breathe

You may wonder where their nose is or how they breathe air. Well… dolphins have a small hole on the top of their head, which they open when they surface and close very tightly when they submerge in the water..

This hole is known as a "blow hole" and is roughly equivalent to the holes in your nose. We can say that dolphins do the same thing that you do when you swim in a pool, letting air out through your nose when you lift your head from the water and introducing it through your mouth and holding your breath for a few seconds when you submerge it again..

But there is a difference: dolphins do not use their mouth to breathe, this to avoid drowning when feeding underwater. Therefore, all the air they need enters through the blow hole and through that same hole is that they release the air that they have processed to take back on the surface of the water, and so on over and over again throughout the day..

Dolphin characteristics

Dolphins under water

You probably have an idea of ​​what a dolphin looks like, but if you don't, you should know that dolphins are animals that have elongated bodies, very similar to other aquatic animals such as sharks, which are a type of fish..

Generally their skin is gray in color, but there are also dolphins with skins that have mixes of black and white, such as killer whales, for example. This skin is extremely delicate: it can be injured easily, although it has the quality to heal very quickly.

Like whales, dolphins have, under their skin, a layer of fat that protects them and serves as an insulator; This is especially helpful when swimming in cold water, as your body should always be at a constant internal temperature.

The size of dolphins varies greatly according to the species, but generally averages between 1 and 10 meters in length and between 40 kilograms and several tons in weight!!

The bottlenose dolphin, for example, measures between 2.5 and 3 meters long and weighs between 130 and 300 kilograms, while the killer whales or killer whales, which are the largest dolphins, can measure up to 10 meters long and weigh more of 9,800 kilograms, which is almost 10 tons.

On the other hand, there is Hector's dolphin or white-headed dolphin, which is one of the smallest in this group, since it barely reaches 1.2 meters in length and less than 50 kg in weight..

Fins

Its elongated body has two fins, one on each side, and it also has a triangular fin on its back. They have an elongated, beak-shaped snout, where their conical teeth meet.

Like many fish, dolphins have a tail that is very important to propel themselves during swimming, however, this tail is horizontal and not perpendicular to the body, like that of fish..

Intelligence and behavior

Jumping dolphins

Dolphins are among the most intelligent animals on the planet, they are very sociable and friendly and learn quickly, that is why they can be trained very easily when kept in captivity, especially in animal recovery centers and in aquariums..

These animals are said to be as cunning and intelligent as apes, so they may have an intelligence more similar to yours and other human beings than any other animal on Earth..

Dolphins are very friendly and playful animals. They are usually chatty, as they are all day emitting a variety of sounds such as hisses, grunts, barks, squawks, clicks and many more, which not only help them to hunt, but also to communicate with each other..

A very peculiar characteristic of these animals, as well as other aquatic and terrestrial mammalian animals, is that the young remain for long periods of time with their mothers after they are born, so that they can protect them and teach them to fend for themselves in waters. open.

This is known as parental care and it is not true for all animals, although it is true for all human beings like you and for other mammals such as elephants, whales and others.

Another very curious aspect of these aquatic mammals is that they generally tend to members of their group who get sick or suffer an injury, as well as you and your friends take care of each other when they are together..

Dolphins can see both above and below the water, although their eyes can only help them see in different shades of gray and in the green-blue spectrum..

Do they sleep?

Although perhaps it is not a question that you have asked yourself, dolphins have a very curious way of "sleeping" or "resting": they are able to "turn off" one part of their brain, leaving the other on and alert, both of the presence of predators as well as other members of the group with which they live.

In addition, this allows them to continue breathing, because even when they rest they must continually rise to the surface of the water to take in air and submerge again..

What do dolphins eat?

Dolphin eating

Dolphins are carnivorous animals, which means that they feed on the meat of other animals that they hunt and that they are usually swallowed whole, so that the spines do not hurt their throats. Some species of dolphins migrate when they do not get enough food, but they are not characterized as migratory animals.

Their preferred prey is squid, but they also feed on different types of fish and crustaceans, which they get in the water thanks to a complex system of echolocation.

Like many bats, related flying mammals, dolphins, through echolocation, are capable of emitting sound waves under water and of receiving the waves that are returned when they collide with any object or animal that is close to them in the water.

The way these waves are returned allows them to know what size and shape the object they collided with is, how far it is and how fast or slow it is moving ... it is as if dolphins could see through sound!!

Although echolocation is a powerful hunting tool, dolphins do not feed themselves: they are always in groups of 5 to several hundred dolphins, helping each other to hunt within large schools of fish..

Dolphins have two stomachs

Maybe you did not know that dolphins, unlike you, have two stomachs: one they use to store food in case they spend a long time without getting prey and the other they use to digest some of their prey and have energy to swim, play , communicate and live in general.

In addition, another curious aspect of these animals is that they do not drink water like you do, but that all the water they need is obtained from the fish they eat..

Dolphin life cycle

Dolphins are relatively long-lived animals, since it has been determined that some species can live more than 50 years.

These do not reproduce until they are more than 5 years old and when they do, usually in warm seasons, the females give birth to a single young after 8 to 17 months of gestation, depending on the species..

Generally they are preyed upon by sharks and killer whales, but in reality the main current vulnerability of these graceful animals derives from human beings, since pollution, the lack of fish due to uncontrolled fishing and the indiscriminate use of extensive fishing nets, make dolphins increasingly threatened.

References

  1. Kardong, K. V. (2006). Vertebrates: comparative anatomy, function, evolution (No. QL805 K35 2006). New York: McGraw-Hill.
  2. Hickman, C. P., Roberts, L. S., & Larson, A. (1997). Integrated principles of zoology. 10th edn. Boston: WCB.
  3. Dolphin Research Center. (n.d.). Dolphin facts for kids. Dolphin Research Center. dolphins.org
  4. Encyclopaedia Britannica. (n.d.). Dolphins. Britannica Kids. kids.britannica.com
  5. World Wide Fund for Nature. (n.d.). Top 10 facts about dolphins. World Wide Fund for Nature. wwf.org.uk

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