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Welcome to the animal section of exploration.tv. You will find here an ever-growing knowledge base about animals, their classification, as well as addictive animal lists.
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Exploring Wildlife
Wildlife is a primary reason for exploring, and little can beat the joy and sense of privilege of being able to observe a wild animal in its natural habitat.
The Animal Kingdom is incredibly diverse. As much as we all feel we know a lot of different animals, there are also so many most of us have never heard of, that are just as fascinating and beautiful. The animal lists below are a good place to get started!
Animal Lists
Browse and discover hundreds of animals by first letter, by color, or by physical feature, among others.
Animals Around The World
Find out what animals live in different continents, regions, countries, or types of habitats.
Classification of Animals
With millions of different species, animal diversity on our planet is astonishing. It is estimated that more than one million species of animals call our planet home.
Scientists have classified animals into different groups. This makes it much easier to study them and understand how they are related to each other.
Taxonomy
Taxonomy is the science of organizing living organisms into different groups, according to the characteristics they share. These groups are called taxa (plural of “taxon”).
There are 8 main hierarchical levels of taxa currently in use:
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Given the complexity of the living world, subcategories are sometimes necessary, such as superclasses (a higher group of classes), suborders (a lower group inside an order), or subspecies, for example.
We owe this classification system to Carl Linnaeus, a Swedish botanist who lived in the 18th century. That is why this system is known as the Linnean Taxonomy.
For example, the whole taxonomy of the tiger looks like this:
- Domain: Eukaryota
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Carnivora
- Suborder: Feliformia
- Family: Felidae
- Subfamily: Pantherinae
- Genus: Panthera
- Species: tigris
The binomial nomenclature – the fact of naming living organisms by their Genus and species names – is also a creation of Linnaeus. For example, the scientific name of the tiger is Panthera tigris. By convention, Genus and Species Latin names are written in italic.
Scientific names of animals are in Latin because it is a dead language that will not evolve anymore, ensuring that the classification will remain consistent over time.
Vertebrates & Invertebrates
We can split animals into two main categories. Vertebrates are animals that have a spine, or backbone. Invertebrates are animals that do not have a backbone.
Vertebrates make up their own phylum, called Chordata. They are organized into five different classes of warm-blooded and cold-blooded animals:
- class Mammalia – Mammals
- class Aves – Birds
- class Agnatha – Jawless fish
- class Chondrichthyes – Cartilaginous fish
- class Osteichthyes – Bony fish
- class Reptilia – Reptiles
- class Amphibia – Amphibians
Invertebrates are split into different phyla:
- phylum Porifera – Poriferans
- phylum Echinodermata – Echinoderms
- phylum Cnidaria – Cnidarians
- phylum Mollusca – Mollusks
- phylum Annelida – Annelids or segmented worms
- phylum Platyhelminthes – Flatworms
- phylum Nematoda – Nematodes or roundworms
- phylum Arthropoda – Arthropods, itself split into subphyla and classes such as Arachnida, Crustacea, Insecta, and Myriapoda.
Types of Animals
Let’s now take a closer look at the different groups of the Animal Kingdom.
Mammals
Mammals are warm-blooded vertebrates of the class Mammalia. One of their characteristics is being able to produce milk with mammary glands, to feed their young.
Many well-knowns animals are mammals.
Birds
Birds are vertebrates that make up the class Aves, and they are also warm-blooded.
Some of their most important characteristics are that they have feathers, a beak, and they lay eggs.
Fish
Fish are in reality split into three categories – jawless fish, cartilaginous fish, and bony fish.
They are all aquatic, they breathe through gills and they are cold-blooded.
Reptiles
Animals of the class Reptilia are commonly referred to as reptiles. They are cold-blooded and have scales.
They include animals with four limbs like turtles and crocodiles, and animals with no limbs, such as snakes.
Amphibians
Amphibians are cold-blooded vertebrates of the class Amphibia. They name refers to the fact of being both aquatic and terrestrial.
A main characteristic of amphibians is that most species start their life as an aquatic larvae.
Mollusks
Members of the phylum Mollusca are commonly called Mollusks, or Molluscs. They are the second-largest group of invertebrates after Arthropods, and close to a quarter of marine species are Mollusks. Many have a calcareous shell.
Insects
Insects are a class of Arthropods, and they are invertebrates. Instead of having a backbone, they have an exoskeleton.
They body is made of three different parts: the head, the thorax, and the abdomen. They have 6 legs.
Arachnids
Arachnids are another class of Arthropods that include spiders and scorpions. They have 8 legs.
Their body is made of two parts, the cephalothorax and the abdomen. Unlike insects, they have no wings or antennae.
Crustaceans
Crustaceans are invertebrates of the class Crustacea, belonging to the phylum Arthropoda. They include crabs, lobsters, and shrimp, among others.
Their body is made of a head, a thorax (sometimes merged), and an abdomen with an exoskeleton.
Myriapods
Myriapods are members of the class Myriapoda, another class belonging to the phylum Arthropoda. As such, they are also invertebrates.
Their name comes from Greek, meaning “ten thousand feet”, and this group includes millipedes and centipedes. All myriapods are terrestrial.
Cnidarians
Cnidaria is an aquatic phylum of invertebrates (mostly in marine ecosystems). Best-known cnidarians include jellyfish, sea anemones, and corals.
Their most notable feature is their tentacles bearing highly specialized cells, cnidocysts, used to capture their prey. When one gets stung by a jellyfish, it is the action of the cnidocysts.
Echinoderms
Commonly referred to as Echinoderms, members of the phylum Echnidermata are only found in marine environments. They have an ossified skeleton.
Sea urchins, starfish, brittle stars, sea cucumbers, and crinoids are all echinoderms.
Poriferans
Porifera is the phylum of sea sponges. These invertebrates are some of the simplest animals, as their body lacks any organization into tissues and organs.
The name Porifera means “that bears pores”, and it is a good description of their body. Sponges are full of spores, allowing the circulation of the water through them.
Annelids
Annelids are invertebrates members of the phylum Annelida, and they are known as segmented worms. Indeed, their body is made of a series of segments, all having the same organs.
Annelida is a very large group of worms, that include commonly seen creatures like earthworms and leeches.
Flatworms
The phylum Platyhelminthes is the phylum of flatworms. Unlike annelids, they have no segments, and they are quite simple animals without any circulatory and respiratory organs.
It is their flat body shapes that allow the diffusion of oxygen through their body. Their digestive system has only one opening, acting both as a mouth and an anus.
Nematodes
Nematodes are a third phylum of worms (phylum Nematoda), commonly called roundworms. They can be found in virtually every ecosystem on the planet, including the human body.
They are tiny, thin worms, sometimes microscopic.
Frequently Asked Questions About Animals
How Many Species of Animals Are There?
Out of the 8.7 million species that make up life on our planet, it is estimated that there at between one and two million animal species.
How Many Animals Are There in The World?
Animal rights advocate and mathematician Brian Tomasik attempted to estimate the number of individual animals on Earth in a publication in 2009. According to his calculations, there are 20,000,121,091,000,000,000 animals on Earth. That’s 20 quintillion, or 20 billion billion animals.
Yes, human beings are animals. We are vertebrates, mammals, and primates, just like the chimpanzee or the bonobo, our closest cousins. It is our superior cognitive capacity that sometimes led us to think otherwise. There is an excellent article about this question on Science Focus.