{"id":9240,"date":"2024-06-13T13:49:55","date_gmt":"2024-06-13T12:49:55","guid":{"rendered":"https:\/\/neuronicdev.es\/deep-sea-world\/blog\/a-guide-to-animal-classification\/"},"modified":"2025-09-23T10:41:39","modified_gmt":"2025-09-23T10:41:39","slug":"a-guide-to-animal-classification","status":"publish","type":"post","link":"https:\/\/neuronicdev.es\/deep-sea-world\/blog\/a-guide-to-animal-classification\/","title":{"rendered":"A Guide to Animal Classification"},"content":{"rendered":"

Did you know there are too many animals on Planet Earth to count? That\u2019s pretty impressive, but it does make it hard to keep track of them all.<\/p>\n

Luckily, some clever scientists came up with a way to organise and group different species using what\u2019s known as animal classification. This is a complex system that categorises animals based on common characteristics and traits, so they\u2019re easier to organise into groups.<\/p>\n

Not sure how animal classification works? We\u2019ll get you up to speed in this comprehensive guide, which includes a free animal classification chart for you to download, print out and take away.<\/p>\n

What is an animal?<\/h2>\n

Sure, it may sound like a pretty straightforward, self-explanatory question. But have you ever stopped to consider what an animal actually is? And perhaps more importantly, just how many animals there are on our planet?<\/p>\n

If the answer\u2019s no on both counts, then let us rectify that.<\/p>\n

Animals are living creatures that move, eat, sleep and live of their own free will. They breed and produce offspring to ensure the survival of their species, relying on senses like sight, smell, hearing and touch to interact with the world around them.<\/p>\n

Remarkably, scientists are reluctant to even estimate just how many animals there are on our planet. Some live on land, some live in the sea, and some live in the sky, but it\u2019s impossible to put a number on quite how many mammals, insects, reptiles, and birds there are.<\/p>\n

Indeed, there are so many animals on planet Earth that scientists developed a way to organise them into logical groups, simply so that they could be researched and referenced more easily. And thus, animal classification was born.<\/p>\n

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What is animal classification?<\/h2>\n

Animal classification is when different species of animals are identified, named and organised into groups based on a set criteria. Swedish biologist Carl Linnaeus developed the system in the 18th century, referring to it as \u201cbinomial nomenclature\u201d. You don\u2019t need to remember that fancy term, but you do need to know the basics of how animal classification works.<\/p>\n

Essentially, there are seven categories within the animal classification system, into which every animal on Earth is sorted. This starts with \u201ckingdom\u201d, which is the largest group of animals, and trickles down to \u201cspecies\u201d, which is the smallest.<\/p>\n

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  1. Kingdom<\/strong><\/li>\n
  2. Phylum<\/strong><\/li>\n
  3. Class<\/strong><\/li>\n
  4. Order<\/strong><\/li>\n
  5. Family<\/strong><\/li>\n
  6. Genus<\/strong><\/li>\n
  7. Species<\/strong><\/li>\n<\/ol>\n

    Within \u201ckingdom\u201d, animals are divided into two main groups: vertebrates and invertebrates. This is pretty much the starting point for classification, with animals further categorised until their species can be easily defined.<\/p>\n

    With that in mind, let\u2019s take a closer look at the main differences between vertebrates and invertebrates.<\/p>\n

    What is a vertebrate?<\/h2>\n

    Getting to grips with what vertebrates are is super simple. The term refers to any animal that has a backbone inside their body. Yep, you\u2019re right, that includes you!<\/p>\n

    Of course, vertebrates are a pretty huge group of animals, comprising everything from fish and amphibians to mammals and reptiles. But that\u2019s where animal classification comes in, neatly organising each lifeform to the point where its exact species is clear.<\/p>\n

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    Which animals are vertebrates?<\/h3>\n

    Let\u2019s take a closer look at all the animals that fall into the vertebrate camp, starting with one of our favourites here at Deep Sea World: fish.<\/p>\n

    Fish<\/strong><\/h4>\n

    Fish are vertebrates that live in our seas and oceans, as well as in freshwater rivers and lakes. While they may have a backbone like mammals, that\u2019s the only similarity between them and other vertebrates.<\/p>\n

    One of the standout features of fish is the fact that they don\u2019t breathe air. Instead, they have gills that allow them to breathe underwater. They\u2019re also cold-blooded, which means they\u2019ve evolved ways to survive in waters of different temperatures.<\/p>\n

    Fish can be microscopically small or absolutely huge. Indeed, it\u2019s hard to believe that you get animals like the sand tiger shark <\/a>(Carcharias taurus)<\/em><\/a>in the same animal classification category as the likes of porcupine pufferfish <\/a>(Diodon holocanthus)<\/em><\/a>and the big-bellied seahorse <\/a>(Hippocampus abdominalis)<\/em><\/a>.<\/p>\n

    Amphibians<\/strong><\/h4>\n

    As their name suggests, amphibians are just as happy on land as they are in water (because they\u2019re amphibious, <\/em>right?). These cold-blooded animals start life with gills but then develop lungs as they mature, so they\u2019re born in water but migrate to land when they grow.<\/p>\n

    It can be almost hard to believe that amphibians like the golden mantella (Mantella aurantiaca)<\/em><\/a>frog and the weird-looking axolotl (Ambystoma mexicanum)<\/em><\/a>are vertebrates. But just like us humans, these animals have a spine, so they\u2019re lumped into the same category as us (well, for a little while at least).<\/p>\n

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    One other thing to note about amphibians is that they\u2019re cold-blooded, so can\u2019t self-regulate their body temperature. That\u2019s why many of them hibernate during the winter as a means of survival.<\/p>\n

    Reptiles<\/strong><\/h4>\n

    Reptiles look a lot like dinosaurs. And guess what? That\u2019s because they are!<\/p>\n

    Yes, reptiles are some of the oldest animals on our planet, with some species \u2013 including crocodiles and alligators \u2013 having survived the asteroid that wiped out the dinosaurs. Like amphibians, these cold-blooded animals can\u2019t regulate their body temperature, so tend to seek warmth whenever it\u2019s available.<\/p>\n

    Reptiles are a super diverse group of animals, ranging from snakes like the royal python <\/a>(Python regius)<\/em><\/a>to the huge American alligator (Alligator mississippiensis). <\/em>They\u2019re also incredibly adaptive, with some living in arid deserts and others being semi-aquatic, spending most of their lives in temperate waters. Perhaps that\u2019s why they\u2019ve survived and evolved for over 200 million years!<\/p>\n

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    Birds<\/strong><\/h4>\n

    Like their reptilian counterparts, birds are a remarkably old group of animals, with all modern species believed to have evolved from a handful of species that lived during the time of the dinosaurs. That means your friendly neighbourhood blackbird (Turdus merula<\/em>) has a much longer lineage than you might have expected.<\/p>\n

    Unlike reptiles and amphibians, however, birds are warm-blooded, so don\u2019t need to make a special effort to survive in different temperatures. All birds lay hard eggs in nests and many species mate for life, pairing up with the same partner over their lifespan.<\/p>\n

    Mammals<\/strong><\/h4>\n

    Mammals are among the most diverse groups of animals on the planet. They breathe air, are warm-blooded, and are found on virtually every continent on Earth \u2013 as well as in our seas and oceans.<\/p>\n

    Such is the diversity of mammals that this alone shows why animal classification is needed. Mammals include us, humans, along with over 6,400 extant (meaning existing) species \u2013 from primates and seals<\/a> to the biggest mammal that has ever existed: the mighty blue whale (Balaenoptera musculus)<\/em>.<\/p>\n

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    What is an invertebrate?<\/h2>\n

    Now that you know what vertebrates are, it shouldn\u2019t be too tricky to work out what invertebrates <\/em>are. Can you guess?<\/p>\n

    That\u2019s right, invertebrates are animals that don\u2019t <\/em>have a backbone. These animals usually have a soft body or else a hard outer casing covering their bodies, and range massively in size and appearance \u2013 from microscopic mites we can scarcely see to the colossal squid (Mesonychoteuthis hamiltoni) <\/em>that lives in the depths of the deep sea.<\/p>\n

    Invertebrates account for the vast majority of animals on planet Earth, around 97% in fact. To put that figure into perspective, scientists estimate there to be around 66,800 species of vertebrates, with over 1.3 million invertebrates. Incredible!<\/p>\n

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    Which animals are invertebrates?<\/h2>\n

    Here\u2019s a brief look at all the animals classed as invertebrates, including a definition and some example species.<\/p>\n