The Great World of Animals

Avatar of Shaimaa Olwan
Updated on: Educator Review By: Michelle Connolly

Animals mainly depend on plants for nutrition, and some have only partial dependence on them. It devours food and digests it in its internal cavity, and stores the surplus as animal starch or fat. Feeding is animal, that is, by eating food. Animals follow a specific growth pattern, with adult animals having a specific shape and size.

Wild animals are the ones that are naturally designed to live alone in the wild and depend on themselves to obtain food and shelter, as they are independent and do not need human care, and they are considered an essential element of the livestock. They are at risk more than other animals because they are exposed to hunting and predation more than those that live under human care; many species are at risk of extinction.

They usually live in jungles, desert areas, and forests, far from human habitation, almost uninhabited areas. Wild animals are safer when they live far from humans. Their organisms are multicellular and lack a cell wall.

More complex animal forms have well-developed sensory and neuro-motor mechanisms. Most of these organisms are able to move. Animals reproduce by mating a male and a female, followed by the development of the embryonic stages.

Animal Species in the World

All animals in the world belong to a biological kingdom called the animal kingdom, and this kingdom is classified into about 30 divisions, where animals on earth represent about 75% of living organisms. Animals come in two basic types:


Vertebrates include the following groups:

• Amphibians.

• Birds.

• Fish.

• Mammals.

• Reptiles.


Amphibians are distinguished by their ability to live either on the surface of the earth only, in water only, or to combine the two in their living. Sometimes they are on land and sometimes in the water, and it is mentioned that there are about 8,100 species of living amphibians, and scientists estimate the time of their first appearance to be 340 million years ago during the middle Mississippi era.

Amphibian characteristics

Amphibians have distinctive characteristics, including the following:

  1. They are found in warm environments because they are cold-blooded.
  2. Its body is divided into a head and a torso; some have a tail.
  3. Their skin texture varies; It may be smooth or rough without scales, and it contains glands that make it moist.
  4. It lacks fins attached to its body.
  5. It has two pairs of limbs for locomotion.
  6. Breathe through the skin, or the lungs, in addition to the external gills that only adult amphibians have.
  7. The heart of amphibians is divided into 3 three chambers, in addition to having a medium-sized kidney that performs the function of excreting urea and ammonia out of the body.
  8. Fertilisation occurs externally in most amphibians.


Birds belong to the vertebrate class, and there are more than 10,400 living species. The bodies of the birds are naturally covered with feathers. To be distinguished by this feature from other animals, it is worth mentioning that birds have a heart consisting of 4 chambers, like mammals.

Bird characteristics

Birds have very distinctive characteristics, including the following:

  1. Not all birds can fly, but all of them have wings.
  2. Birds use their beaks to catch, divide, and swallow their food.
  3. They lay eggs for reproduction.
  4. It absorbs heat to maintain a constant temperature.
  5. The digestive system allows her to eat whenever she can, as the digestive system of birds has the ability to digest food after a long period of time has passed since it was swallowed.
  6. They have hollow bones.

Examples of birds

Birds are among the most recognisable animals that are seen frequently in daily life, and examples of them include the following:

• albatross.

• chicken.

• Penguin.

• Falcons.

• ostriches.

• Parrot.

• Owls.


Fish are classified as vertebrate animals, and there are many different species of them. They live in freshwater or saltwater, and they come in a variety of sizes, some of which are incredibly small and others of which are enormously giant.

Fish characteristics

Fish has several distinctive features:

  1. They live in the water, as they are unable to live on land.
  2. They have gills to breathe underwater.
  3. They have an airbag that helps them float stably and not sink to the bottom.
  4. They have fins that help them move and swim in the water.

Examples of fish

The fish category includes more than 30,000 species of fish, which is more than the rest of the other vertebrate categories combined, and the most famous of them are the following:

• Sharks.

• eel.

• Salmon.

• Seahorse.

• Lampreys.

• Hagfish.

• Minnows.


Scientists believe that there are roughly 5,400 species of mammals which are categorised as vertebrate creatures.

Mammalian characteristics

Mammals have many distinctive and unique characteristics compared to other animals, and the most prominent of their characteristics are the following:

  1. Its body temperature is stable, as it absorbs heat because they are warm-blooded.
  2. Contains mature red blood cells that do not contain a nucleus inside them.
  3. Some species have fur, while others have human-like hair.
  4. Mammals contain glands that enable them to produce milk to feed their young.
  5. They have a septum between the lungs and the heart.
  6. It contains a lower jaw that connects directly to the skull.
  7. Reproduce by parturition.

Examples of mammals

There are many examples of mammals, the most prominent of which are the following:

• Human

• Deer.

• Dogs.

• Cats.

• Mice.

• Monkeys.

• Bats.

• Whales.

• Dolphins.


Reptiles are known as vertebrate animals that are distinguished by their strong jaws and light-sized skulls.

Reptile characteristics

Reptiles have many characteristics, the most important of which are the following:

  1. They prefer warm places because they are cold-blooded animals.
  2. Its skin is characterized by being dry, rough, and devoid of glands.
  3. It breathes through the lungs.
  4. The heart of reptiles consists of 3 chambers.

Examples of reptiles

Among the most famous examples of reptiles are the following:

• Snakes.

• Crocodiles.

• Lizards.

• Turtles.

• Sea turtles.


There are many traits that invertebrates have in common; however, the following ones stand out:

  1. No spinal column or spine.
  2. It breathes through the skin.
  3. It does not grow very large in addition to its small size.
  4. Depends on others for nutrition.
  5. Reproduce by fission.

Examples of invertebrates

There are several types of invertebrates as well, including:

• Crab.

• Coral.

• Oysters.

• Jellyfish.

• Earthworms.

• Spiders.

• Hedgehog.

• Cuttlefish.

•  Insects

Characteristics of the Animal Kingdom

The following are some general traits of the animal kingdom:

  1. Animals are heterotrophic, multicellular, and eukaryotic creatures. They have multiple cells that contain mitochondria and depend on other organisms for nutrition.
  2. Habitat: Most animals inhabit the seas, fewer numbers inhabit fresh water, and much fewer numbers inhabit the land. Only 800,000 of the 9–10 million animal species that live on the globe are known to scientists.
  3. Size: Animals range in size from oligocellular organisms such as mesozoans— tiny worms, internal parasites of marine invertebrates—to multi-ton animals such as the blue whale.
  4. Bodies: Animal bodies are made of cells arranged within tissues that perform specific functions. Cnidarians and echinoderms have radially symmetric bodies, while most animals have laterally symmetric ones. Primitive animals are asymmetrical.
  5. Movement: Animals have the ability to move, as they show rapid movement compared to plants and other organisms.
  6. Respiration: is a gaseous exchange in which oxygen is taken in, and carbon dioxide is expelled. This process occurs in the organs of respiration, such as the gills. There are other animals that use their skin for respiration.
  7. Digestion: Animals devour food, and digestion occurs in the internal cavity, such as the digestive system in animals, while digestion occurs inside the vacuoles in primitive animals.
  8. Nervous system: The nervous system performs the mechanics of sensation and regulates the organ systems. The nervous system in animals consists of the ganglia or brain, spinal cord, and nerves.
  9. Circulatory system: It distributes nutrients, exchanges gases, and removes waste. This organ consists of the heart, blood vessels, and blood.
  10. Excretion system: the removal of waste products from the kidneys.
  11. Skeletal system: The skeletal system provides support and protection.
  12. Reproductive system: Most animals reproduce sexually by the fusion of gametophyte cells such as eggs and sperm.
  13. Endocrine system: The endocrine glands help control and regulate the body’s systems.

Classification of the Animal Kingdom

The animal kingdom has several branches known as phyla, estimated of 36. The members of each phylum share features that separate them structurally and functionally from other phyla. In the list below are the most famous phyla classified by the traditional biological method:


They are primitive organisms, mostly saltwater sponges. There are approximately 8,000 species today, such as Sycon, Euspongia, and Spongilla.


This group consists of jellyfish and other lower aquatic animals. Today, there are about 15,000 species, such as Aurelia and Adamsia.


This group consists of flatworms, which inhabit seas and freshwater and usually live as parasites inside the bodies of animals, examples of which are Taenia (tapeworm) and Fasciola (liver worm).


The majority of the nematodes in this group are parasitic. This phylum includes about 80,000 parasitic worms, including Ascaris (roundworm), Wuchereria (filariae), and Ancylostoma (hookworm).


It is found in aquatic and terrestrial environments and lives in nature as a free or parasitic. This phylum consists of annelid worms, examples of them include earthworms, leeches, etc.


It is the largest phylum and consists of insects, as it includes more than a million insect species that exist today. There are honey bees, Anopheles, silkworm, lacquer worm, mosquitos, locust, and king crab.


They are the second largest phyla after arthropods and live in water and on land, such as Pila (apple shell), octopus (devilfish), Pinctada (pearl oyster), Aplysia (sea hare), Sepia (squid), Dentalium (canine shell), Chaetopleura (multi-shelled).


This phylum’s animals can be identified by their notochord, hollow dorsal nerve cord, and pair of pharyngeal gill slits. Fish, reptiles, and mammals are all part of the sophisticated phylum known as vertebrates.

Animal Kingdom Groups

There are three major groups in the animal kingdom:

  1. Herbivores: depend on plants for their nutrition.
  2. Carnivorous: a group that preys on other animals.
  3. Polyphagous: a group that eats both meat and plants.

There are smaller groups within these groups.


Some species of herbivores feed on superficial earth grasses. Giraffes, cows, deer, elephants, zebras, and other species eat tree leaves and soft branches.

The different types of teeth of each type; herbs are harsh and often dusty or have sand on them, so the animal needs to chew them well. As a result, whereas animals that consume leaves and fruits have shorter teeth, those that graze on herbs have longer teeth that can tolerate repeated use.


The majority of other animal species are preyed upon by carnivores, which comprise everything from microscopic organisms to highly adept hunters like wolves, tigers, and lions.


A male lion (Panthera leo) and his cub feed on the carcass of an African buffalo in northern Sabi Sand, South Africa. Many carnivores are experts at hunting and employ a variety of techniques to capture their prey. These techniques vary depending on how the prey defends itself, and many predators rely on intuition when looking for food. They expect to find their prey somewhere and rely on their senses to find prey.

Some waterfowl search in the mud and in the shallow waters; perhaps they may find some worms or other small animals. Huge cats, like lions and cheetahs, crawl quietly and slowly, hiding their bodies among the weeds until they are near the prey, and the falcon stops moving in the air until the eyes of its prey turn away from it and pounce on it.

The ambush is the common method of hunting animals. They hide without movement until their prey approaches them, and many animals that follow this method improve camouflage so as not to appear. Some spiders become coloured like the colour of the branches in which they hide, waiting for the unsuspecting insect.


Several species will consume any meal that is put in front of them, whether it be meat, herbs, or plants. Invertebrates such as starfish eat the remains of organic matter of different compositions.

Animal Balance in Nature

There are multiple factors that create balance in nature. All forms of life depend on water and air, as well as other things in the environment.

Food chain

The food chain is the relationship between many creatures; for instance, plants like cannabis provide food for herbivores like zebras, which in turn provide food for carnivores like lions.

Hashish is a food source for various grazing herbivores, and each herbivore is a prey item for one or more carnivore species. It is the process by which energy flows up the food chain from the base to the top. These intricate food chain links are known as autotrophs.

The chain continues with cannabis at the base, followed by buffalo, and lions at the top of the food chain, who eventually disintegrate to return to the plant, and so on, until one of the species in the pyramid goes extinct, breaking the chain. The collapse of the entire food chain and nature is always spoiled by humans.

Animal herds

Animals typically coexist as separate families or in groups, such as herds of deer, flocks of swallows, or schools of fish. However, occasionally, two different species will partner up for a variety of reasons that are always advantageous to both parties. For instance, the sea anemone attaches itself to the hermit crab as a form of protection. The anemone feeds on the crab’s leftover food (crab).

In tropical regions, many types of birds perch on the backs of large animals such as buffaloes, giraffes, and deer, so they eat the birds and help clean the animal, and there are birds Others find their food inside the crocodile’s open mouth, so they enter and devour whatever worms and leftovers they find between the teeth. In return, these birds warn the crocodile if some danger is approaching.

Symbiotic partnership

Sometimes the partnership is so close that one of the two partners cannot survive without the other, and this is what we call (symbiosis); lichen or lichens are composed of two plants joined together; moss and parasitic.

The green alga makes food, and the parasite reproduces, and therefore we often find lichen living on bare rocks and burial stones, and ruminant animals such as cows live very small animals inside their stomachs, and the mission of these animals is vital for cows because it causes the dissolution of cellulose, which occurs in plants, and the cow cannot do that by itself but rather relies on these small animals to soften the herbs in their stomachs when they swallow them.

After time has passed, the cow returns and takes out this food and regurgitates it, i.e. chew it well and swallows it completely, and with the way the animal, especially the ruminant, can obtain the maximum benefits from food, and there is another type of partnership that occurs in the simple marine animal, the hydra, with many reefs such as hair. This animal allows precise types of algae to live inside its tissues, providing them with housing, and these algae provide it with oxygen.


In other types of partnership, there is no interest in one of the two partners and not the other, as the parasite lives at the expense of its other partner. Many worms live inside the bodies of animals and feed on their food, fleas live by sucking the blood of other animals, and some types of frogs and even other plants live on types of trees, and it remains.

As long as the number of parasites living on a body does not reach a set rate, the situation is fine. Nevertheless, if the number rises or if these parasites penetrate the wrong body, it may cause disease in the host or even lead to death in some cases.

Germs transmitted by mosquitoes, rats, or fleas can be fatal, but mosquitoes or fleas are not harmed. A parasite may spend a lifetime inside a host’s body, and it is usually without legs, so it clings to its dogs or mouth and lives its life eating and laying eggs, and many parasitic insects live this way.

Wild Animals

Although wild animals are considered an important component of the life balance, several species are in danger of being extinct as they are more vulnerable to predation and hunting. Wild animals usually live in uninhabited areas, as forests, deserts. We will get to know many types of wild animals through this article.

Types of Wild Animals

The types of wild animals differ between predators and pets, as other names call them, and here we will get to know them clearly:


Predators are mostly wild animals living in forests and prairies far from humans as they cause great danger to humans, and are called wild animals which humans cannot deal with directly unless they are tamed, and most of them are carnivores and are scientifically named according to the nature of their food Second consumers, as they feed on the first consumers, which feed on products, namely plants, among the most important predatory wild animals: the lion, the fox, the wolf, the bear, the leopard, the hyena and others.

Types of Predators

Predators are of many and varied types, and their numbers are large, and we will list here the most famous and widespread types of these animals, the most prominent of which are:


The cheetah is one of the most dangerous predators because it hunts other animals in a terrifying way to get its food. It eats both mammals and reptiles, is most active at night, and has the ability to climb tall trees while carrying its prey in its teeth. The cheetah is well-known to man as a symbol of bravery and strength.


Wolves prefer to eat large mammalian family members, such as goats and cows. They are found in North America and Eurasia. Wolves are distinguished by their grey fur.


The lion is an African animal, most of its activity is at night, as it spends the largest time of the night chasing prey, and the lion needs a large amount of meat to feed on, and its weight reaches approximately fifteen pounds, and although lions are on the throne of predators In terms of strength and ferocity, it does not prey on humans, although it used to do so in the past.


The red fox is a predatory carnivore that once threatened farmers and their livestock significantly. However, as it no longer poses a threat to humans, its activity has decreased significantly in recent years. The hyena is an African mammal that is more active at night. Despite its small size, it is one of the most dangerous to human life because of its rapid speed and propensity for frontal assaults on humans.


One of the most dangerous crocodile species is the Australian crocodile, which may be found on the Asian continent. The crocodile’s size has increased for at least thirty years, making it a very large animal. It is a very fierce animal that attacks humans directly when they come close to where it is.


Pets are accustomed to living in the wild, far from humans; they are terrified of humans. However, when they are acquired and raised by a person, they become accustomed to their presence and lose their fear towards them. As for those that did not approach humans, they see humans as a great danger to their lives, as they also see that in predatory animals.

All domesticated animals are classified as wild until they are domesticated and raised by people. This is because as they get to know people and become accustomed to their nature, they understand their presence in their lives and do not view them as enemies.

In contrast, if pets spend a long time in the wild, away from people, they eventually turn into wild animals that may terrify people due to their behaviour, making it difficult for them to domesticate them.

Types of Pets

We all know many animals as pets, next are some of the common pets known to us; however, some of them might be a surprise.

While some people may like taking care of tigers, monkeys, or crocodiles, the majority of these animals are either destined for extinction owing to a lack of a suitable environment and food or given to zoos. Pets can be kept in the following categories based on where they were raised:

  1. Household pets: animals maintained as household pets include cats, dogs, and some species of birds, such as canaries, parrots, jays, magpies, and others. Pets that live in vivarium pets, which are animals that need specific conditions of humidity and heat, including lizards, turtles, frogs, toads, and also snakes.
  2. Aquarium pets: including ornamental fish of various kinds.
  3. Cage pets: Animals raised in cages inside or outside the home under specified circumstances that give protection for the pet are referred to as “pets that live in cages,” and this includes rabbits, mice, and chinchillas.
  4. Paddock pets: are animals kept in stables outside the home, including horses, donkeys, and mules.

What are the benefits of owning a pet?

Here are some of the benefits of raising pets:

  1. It helps lower blood pressure.
  2. It reduces cortisol hormone levels, which rise in the blood when exposed to stress.
  3. It enhances mood and reduces loneliness.
  4. It reduces the tension, which can be achieved when watching aquariums breeding ornamental fish. Some hospitals and nursing homes use dogs to relieve anxiety and stress among patients. However, some researchers advise ensuring that patients are not exposed to germs from pets before allowing them to communicate with them.
  5. Encourages physical activity, especially when walking dogs.
  6. It enhances social skills and the spirit of cooperation. It reduces bad behaviour among children with hyperactivity and lack of attention, according to a study conducted by researchers to monitor the effect of the presence of dogs in a class that includes people with hyperactivity and lack of attention. Another study indicated that children with autism spend several minutes playing with animals led to a decrease in their level of anxiety.
  7. Living in a house with pets at an early age reduces the chances of developing allergies and asthma, provided that the child is not allergic to this type of animal in the future.
  8. Promotes a sense of responsibility. A study was conducted on a group of adolescents with diabetes who were assigned the tasks of caring for and feeding ornamental fish. The study indicated that they were more committed than other patients to checking their blood glucose levels on time.

What are the possible dangers of keeping pets?

Many people accept pets at home without knowing that there are many diseases that can be transmitted from the animal to them, especially children and pregnant women.

Therefore, some matters must be taken into account when dealing with animals, such as washing hands after touching them or their food and tools, preventing children from kissing them, taking care of their cleanliness constantly, showing them to the veterinarian periodically, and making sure to give them the necessary vaccinations.

Thus, the risk of contracting diseases that may be transmitted to humans can be reduced, including the following:

The flu

Influenza, including bird flu, can be transmitted from infected cats to humans in rare cases.


When humans are bitten or scratched by infected dogs and cats, they carry the potential of being infected by the plague. Air can also be a means for transmitting the bacteria that cause the disease.


Humans may become infected with salmonella bacteria when touching infected turtles or touching their tools and cages.

Cat scratch disease

If the cat is infected with the bacteria, the person is likely to be infected. Its symptoms include fever, headache, and fatigue. In order to avoid infection, it is recommended to wash the cat bite and scratches immediately with soap and water.


It is a disease that is transmitted to humans through the urine of an animal infected with a type of spiral bacteria. In order to avoid infection, pet owners are advised to wash their hands when touching animals or when touching belongings that their urine can reach.

What to consider before owning a pet?

Before deciding to get a pet, take into account the following:

  1. It is a long-term commitment to the animal.
  2. Animals like cats and dogs live longer than other pets, as they can live up to 10 or 15 years.
  3. Ensure the financial ability to own a pet that requires high expenses that include covering food, toys, vet visits, treatment, and more.
  4. Having a pet requires attention and care. The lifestyle must be evaluated if it is appropriate or not. For example, if the owner works for long periods and travels constantly, he cannot have a pet, as he needs attention and plays with him constantly so that he does not feel isolated, which may lead to behavioural problems. Later.
  5. Ensure that none of the family members suffers from allergies to the fur and hair of pets. This can be confirmed by interacting with a friend’s pet before acquiring the pet.
  6. Ensuring the ability to train the pet Training the pet to relieve itself in the designated place, and this takes time and effort.

Best pets to own

Here are the best pets to own:


Dogs are the best pets, and of course, dog breeding needs commitment from its owner and his entire family, and he needs some attention by taking him to exercise and providing the space he needs.


The second best pet after dogs, and it is characterised by its delicacy and its need for a lot of love. It also needs attention, but at a lower level than dogs, as it needs to provide food and a litter box.


Rabbits are among the pets that families love to have, as they are smart and curious animals that children love, and they also need some attention by providing them with food, cleaning them, and doing some exercise, and they need interaction around them, especially if they do not have a companion.


The hamster mouse is the most favourite pet among children, and there are a number of different breeds available from it, some of which are very social, and others prefer solitude, so you must make sure of its breed when buying a hamster, and the hamster needs to eat water and food, and provide a place to sleep, and nesting materials.


Fish is a great choice of pets suitable for young children, and you can buy or make a small aquarium at first with some goldfish, as children love to feed them, take care of them, and enjoy their company.

If you enjoyed learning about this stunning animal, why not check out more exciting facts about other animals: Koalas, Land Animals, Sharks, Raccoons, Moon and Sun Bears, Rats, Chickens, Cats, Pandas, Monkeys, endangered animals, waterfowl and Whales.

Why not subscribe to our LearningMole Library for as little as £1.99 per month to access over 2000 fun educational videos.

Leave a Reply

Your email address will not be published. Required fields are marked *