Quantifying the Amazing Diversity of Life: How Many Animals Are in the World?

How Many Animals Are in the World?

I love nature. There is something amazing about being outside and seeing how many different animals, insects, birds, fish, and more are actually present in our world.

The living species that exist around the globe continually change, and new species are identified almost daily.

Sadly, some existing species are also annihilated from the animal kingdom by evolutionary pressures and the human impact on the earth. But back to my question: Just how many animals are in the world?

I decided to find out.

Top 10 Most Startling Stats

How Many Animals Are in the World?

Exotic Animal Laws by State

There are many diverse opinions about just how many animals are in the world, especially if the idea of “animals” includes fish, insects, birds, and more. 

And while we may find out how many animals are known to be in the world, we don’t actually know how many animals are in the world as some animal species haven’t even been discovered yet.

The Estimated Number Described Species in the World Is 2.16 Million, From the Total Species Population of 8.7 Million. (IUCN)

Of the 8.7 million species that exist on earth, we would probably consider 2.16 million species to be animals; however, the other 0.3 million species are made up of living animals, too—such as amphibians, corals, and crustaceans.

More Than 62,000 Vertebrate Species Have Been Identified (Libre Texts Biology)

how many species of animals are there

Of the animal species that have a spine (also known as vertebrates), there are 62,000 species that have been identified as having existed or currently existing. (source)

This list includes extinct animals like dinosaurs and species that have evolved into new species.

97% of All Animals Are Invertebrates, With a Total Species Population of 1.3 Million (National Geographic, Hawaii.edu)

The largest chunk of the 2.16 million species that exist across our planet belongs to the invertebrates, or species that have no spinal column.

In fact, 97% of all animals are invertebrates—so think twice before you smash that spider crawling across your desk; they outnumber you and me! (source)

In the US Alone, There Are More Than 140,000 Invertebrate Species (NWF)

I’m not a fan of bugs. I mean, I love all animals, but I tend to avoid the “creepy crawlies.” Yet, a massive 140,000 invertebrate species exist in the US alone. (source)

Note: this is not the number of members of those species but the species alone.

Sadly, many people don’t appreciate the “bug” part of our biodiversity, so they may choose to exterminate insects and other critters instead of first finding out how helpful or harmful that invertebrate is. Because of this, over 200 species of invertebrates in the US have become endangered.

The Estimated Species of Insects Is 10 Quintillion (Pest World for Kids)

Pests in the world

Believe it or not, there are a total number of insects to the tune of 10 quintillions on earth. (source)

Yip, you read that right! 

Imagine bugs to a total of 10,000,000,000,000,000,000. Even the zeros make my skin crawl! But hey, live and let live (after all, the bugs outnumber us by quintillions).

More Than 6,495 Species of Mammals Have Been Identified by Scientists (Research Gate)

Back to the warm and loving mammals, there are more than 6,400 species of mammals that have been officially identified on Earth. If you can’t remember your high school biology, mammals are animals that nurse their young, such as cows, pigs, and human beings (we’re animals, too). (source)

There Are 12,060 Species of Reptiles in the World (IUCN)

Species of Reptiles

If you have jumped on the reptile bandwagon and have a beardie looking at you from its vivarium, you probably wonder how many species of reptiles have been identified on Earth.

The Current Amphibians Database Shows There Are 8,698 Existing Species of Amphibians (Amphibians Web)

how many species of land animals exist

Perhaps you have a great big bullfrog glaring at you through the sides of your terrarium? Well, satisfy your curiosity, as there are 8,698 species of amphibians.

Amphibians, as you may know, are animals that start life in water and continue it on land, like frogs.

Approximately 300 Species of Amphibians Are Found in the US (USGS)

The US has an ARMI approach to amphibians, that is, the Amphibian Research and Monitoring Initiative (ARMI), to track just what has been happening in the amphibian kingdoms. (source)

We do have a responsibility to keep an eye on all living animals, including slippery amphibians, as 300 of the 8,698 species exist in the US.

The Recently Estimated Number of Fish in the World Is 3.5 Trillion (World Atlas)

fishes - life forms

Not forgetting your goldfish in its nice tank, the answer to how many fishes are in the world’s waterways and oceans is estimated at 3.5 trillion. (source)

While that may seem like a lot of fish, we are fast depleting the world’s fish population as fish is a major source of protein for most of the world’s humans.

There Are More Than 11,000 Species of Birds in the World (Birdlife International)

I can’t leave out my beloved chickens in this headcount of animal species, and there are 11,000 species of living birds in the world.

I say living birds because so many bird species have been driven to extinction by human activities like deforestation and because of the use of agricultural poisons and herbicides.

The number of species that are extinct among our feathered friends is a shocking 129 species.

How Many Species of Animals Are There?

how much animals are in the world

Okay, so I now had a fair indication of how many animals are on Earth, but I wanted to know just how many species of animals are living on this crazy rock spinning around the sun with me. 

I’m also not alone in wanting to know this, and the International Union for Conservation of Nature’s (IUCN) Red List for animals nearing extinction keeps track of all the animal species on earth and releases updated counts each year.

There Are 1.05 Million Described Species of Insects (IUCN Red List)

According to the IUCN Red List, there are 1.053 million species of insects on earth. Of this number of species, only 1.2% of all insect species recorded have been evaluated for their status as critical or endangered for the Red List. (source)

I can just imagine how many insects are actually endangered, but we don’t know the exact number yet.

The Described Species of Birds and Reptiles Are 11,197 and 12,060, respectively (IUCN Red List)

how much animals are in the world

The vast diversity of our planet’s wildlife is exemplified by the astonishing numbers of described bird and reptile species. According to the IUCN Red List, a staggering 11,197 bird species grace our skies, while 12,060 reptile species slither, bask, and swim across various terrains.

This immense biodiversity underscores the importance of conservation efforts to protect these creatures and the habitats they call home.

About 6,596 Described Species of Mammals Exist in the World As of 2021 (IUCN Red List)

Actual number of total animals

My fellow mammals and I make up 6,596 species, of which 91% have been evaluated for the Red List according to the IUCN Red List.

86% of All the Land Species and 91% of All Sea Species Have Not Been Discovered Yet (Phys.org)

Yeah, you read that statistic correctly. A staggering thought: Most of all land species (86%) and even more (91%) of sea species haven’t even been discovered yet, according to a study published by PLOS Biology.

That means that we only know 14% of all land animal species and a mere 9% of all species that live in the oceans of our planet.

Types of Animals in the World

There are many different types of animals in the world, and these species can be divided into categories of mammals, reptiles, amphibians, fish, invertebrates, and birds.

individual animals in the worlds

Mammals

Mammals are any animal that gives live birth to their offspring, such as humans, cows, pigs, antelope, dolphins, and more. Animals that birth their young also suckle their offspring, which is why they are called mammals (as in having mammary glands).

how many animals are there in the world

Since mammals are also vertebrates—they have a spine as part of their bone structure. But, interestingly, not all vertebrates are mammals as a vertebrate, like a crocodile, is a reptile, not a mammal, since it lays eggs (even though it may look after those young, it doesn’t nurse them).

Mammals are also warm-blooded and usually have fur, though dolphins and whales are the oddballs here as they are both cold-blooded and have skin and not fur.

how many animal species are there in the world

A few examples of the 6,596 known mammalian species include:

  • Dogs
  • Cats
  • Humans
  • Primates
  • Equids (horses, zebras, donkeys)
  • Camelids
  • Antelope
  • Bovines (cattle)

Reptiles

3 million to 100 million animal species

Reptiles are vertebrates, and they have a skeleton, including a spinal column. Yip, even a slithery snake has a spine, making it a vertebrate.

A reptile is coldblooded, meaning it has to gather heat from its environment (which is why you see lizards sunning themselves in the morning), and reptiles usually don’t give birth to live offspring but lay eggs instead. 

Some snakes, like boas and pythons, may give birth to live offspring, though these offspring are immediately independent and don’t require any nursing or care from their parents.

When you hold a reptile, it’s not a warm body you can cuddle, though reptiles are intelligent and can make great pets. Reptiles have hardened skin or scales like a snake. Some reptiles, like turtles, also have a shell to protect their bodies.

All reptiles are vertebrates, but, as I mentioned above, some vertebrates are mammals, not reptiles, while other vertebrates may be birds or fish.

all the animals in the world

Some examples of the 11,733 known reptile species include:

  • Snakes
  • Lizards
  • Turtles
  • Crocodilians (which includes alligators)

Amphibians

different animals in the world

When I say amphibian, most people will immediately think: Frog. And you’d be correct, but frogs aren’t the only species of amphibians known to us. 

Amphibians are also vertebrates, and while they may seem fish-like, amphibians have a unique skeletal structure that includes four limbs. Amphibians are also native to aquatic environments, meaning they need water to survive, even though they usually breathe air too.

There are several species of amphibians that live in trees, while others live in pools, rivers, lakes, or even on land. Usually, amphibians lay eggs and have little to no parental care for their young.

When the offspring have hatched, they may go through transformative stages to reach maturity, such as tadpoles that become full-grown frogs after starting in a fish-like shape, then growing a set of forelimbs followed by the back limbs until they resemble their parents.

how many unique species are alive on earth today

Of the 3,000 known species of amphibians, here are a few examples:

  • Frogs
  • Toads
  • Salamanders
  • Newts

Fish

I like eating fish as much as the next person, but I hate the bones. They have bones because, you guessed it, fish are vertebrates too. Fish have scales, and they are coldblooded, but they may or may not give live birth to their offspring.

certain species of animals of the earth

Some fish may raise their young, such as the seahorse, while others simply spawn eggs like salmon and then move on with life.

Fish have evolved over centuries, and since they have the largest habitats on earth—our lakes, rivers, and oceans—there are a huge number of species of fish.

Of the almost 34,000 known fish species (33,600 species to be exact), here are a few examples:

  • Bony fish species
  • Jawless fish
  • Cartilaginous fish

Keep in mind that the number of fish species is more than 34,000 species, as only 91% of all ocean life has been cataloged or identified.

Invertebrates

the vast majority of world's species

While vertebrates have bones, invertebrates have no bones or no spinal column. Invertebrates are usually cold-blooded animals with soft bodies that are not rigid unless they have an outer shell or exoskeleton.

More animals are invertebrates or soft-bodied than vertebrates (with a skeleton).

There are more invertebrates than vertebrate species, and there is also a much greater diversity within the classified species. From tiny micro-organisms that are invertebrates to large animals like the giant squid, there are many different species of invertebrates.

Some of the 1.3 million known species of invertebrates include:

Birds

Finally, we get to our feathered friends, and I am sad to say there are no mammalian birds (though that’s a cool thought). Birds hatch their young from eggs and don’t nurse them. However, all birds are vertebrates, as they have a spinal column and a skeleton.

every animal in the world

Yet, birds have one ability that sets them apart from most other animals—they can fly! Birds have evolved, so their arms have developed into wings, which are powerful enough to generate lift and thrust, creating flight.

Not all birds are flighted birds, and there are a few bird species, like ostriches, that are considered flightless. However, these birds are flightless because they can’t generate enough power to lift their bodies. 

Usually, it’s merely a case of their wings being too small in relation to their bodies. Chickens are an example of this, and while chickens don’t exactly fly hundreds of feet in the air, they can fly high enough to get over obstacles and escape the coop.

Sadly, chickens can’t out-fly slaughter, and even though there are four chickens to each person on earth, we keep slaughtering millions of birds daily.

Of the 11,188 known species of birds on Earth, here are a few examples:

  • Diurnal birds (birds active during the day)
  • Waterfowl birds
  • Flightless birds
  • Shorebirds
  • Aquatic birds
  • Perching birds

Are There More Insects or Fish?

Finally, I wondered what type of animals are the most plentiful on earth. I knew that mammals were not going to be at the top, but I considered whether insects or fish had the most species and the largest numbers of each. Here’s what I found:

There are 34,000 fish species, but there are over 1,000,000 insect species on earth. And the final piece of the puzzle: There are 3,500,000,000,000 fishes on earth, but there are 10,000,000,000,000,000,000 insects on earth.

Insects are a clear winner by a couple of billion.

Perhaps this is why so many countries are considering insects as an alternative protein source, compared to fish or red meat. Anyone for some cockroach and chips?

Are There More Animals Than Humans on Earth?

Are There More Animals Than Humans on Earth?

I love my pets, and I love all members of the animal kingdom, but I wondered, a little fearfully after watching the Zoo series, just how badly we are outnumbered by the other animals on Earth.

So, I considered the animals we keep for food—chickens and cows, specifically.

There Is a Greater No. of Chickens on the Earth (34.4 Billion) Than the No. of Humans (7.764 Billion) (Wonderopolis)

number of chickens in world

Chickens outnumber us by a staggering four chickens to each person on earth. That translates into 34.4 billion chickens for 7.764 billion humans.

Each day, the number of chickens increases as we continue to breed more chickens for slaughter to sate our need for animal protein sources.

The Total No. of Cattle on Earth Is 1.47 Billion, and That of Sheep Is 1.1 Billion, Which Is Less Than the No. of Humans (Wonderopolis)

We humans still outnumber other farm animals, such as cattle and sheep. The world cattle population is estimated at 1.47 billion as the answer to how many cows are in the world, with sheep reaching 1.1 billion animals. (source)

In 9 US States, Cattle Outnumber the Human Population (Beef2live)

From South Dakota, with 4.32 cows per person, to Oklahoma, with 1.12 cows per person, there are 9 US states that have cattle populations that outnumber their human populations.

This means there are more cows than people in 9 out of all American states—interesting herd dynamic, I’d say. (source)

FAQ’S

How Many Organisms Are on Earth?

Living beings, which includes animals and plants, are estimated to be around 2.16 billion. Of course, that number doesn’t include all species that are alive today.

Animals diversify and evolve, which gives rise to new species, and we don’t know many species that exist out of human sight.

Other organisms like bacteria, viruses, and more species that defy definition may not be included in the 2.16 billion number of species.

How Many Species of Land Animals Are There?

There are said to be 6.5 million species of land animals on earth. We can’t know exactly how many species exist on land as only 86% of all land animal species have been fully identified.

What Percentage of Animals Are Vertebrates?

Less than 5% of all animal species are vertebrates, meaning that more than 95% of all species in the animal kingdom are invertebrates or have no spinal column.

What Types of Animals Live Near Volcanoes?

Many different animal species live near volcanoes. What type depends on the kind of volcano, as an underwater volcano will have a different ecosystem than a land-based volcano, and whether or not the volcano is active also has a significant impact.

Underwater volcanoes can support diversity at the species level as there may be all sorts of fishes, corals, and more species. Land-based volcanoes support any number of species, from birds and reptiles to mammals, that may live on or near the volcanoes.

How Many Unique Species Are Alive on Earth Today?

Our planet supports a diverse species spectrum of 2.16 million living animals that includes mammals, invertebrates, vertebrates, fish, birds, insects, and more.

Wrap Up

If you believe that we live in a boring world, I’ve just given you 2.16 million reasons in just the animal kingdom why we are blessed with the most amazing planet to call home.

With so many millions of animal species that have been identified (and there are millions more that haven’t even been named yet), aren’t we lucky to be the only sentient beings—or are we?

Sadly, we are not the dominant species on Earth, yet we are mostly responsible for the extinction and endangerment of many animals on Earth. You can learn about the 40 alarming endangered species and pledge to play your part to protect them!

Talitha Van Niekerk
Talitha is a full-time writer and content creator. She has a passion for animals of all shapes and sizes. Talitha has made it her life’s work to help educate pet owners to build better animal-human bonds so they can enjoy the same unconditional love her five horses, seven dogs, two cats, and an ever-growing flock of chickens shower her with daily. As a writer, Talitha draws on her years as a riding facility yard manager, her own experience, and thorough research to create the best and most accurate information to guide her readers. She loves reading feedback from happy readers who have benefited from her articles and helping pet owners is why she writes. After more than ten years as a teacher, she still wants to educate and inform people so they can make better decisions for their pets. Her happy place is at her computer with her dogs snuggled around her toes, a cat on her lap, or in the saddle.

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