How Many Total Animals  Are There in the World?

Introduction

     Have you ever wondered how many total individual animals there are in the world? Do you have a guess? Continue reading to find out and become more knowledgeable about animals!

The Best Estimate

     So, the quick answer is there are 20,000,121,091,000,000,000 animals. But this number is actually very complicated. One reason it's complicated is because this number is SO BIG! What does it even mean?

     20,000,121,091,000,000,000 is about 20 quintillion, also called 20 billion billion. That's a weird number!

    It's also complicated because it is impossible to actually count all of the animals. So 20,000,121,091,000,000,000 is only an estimate. That means it is a best guess based on theories that might be right or might be wrong. So the actual number of animals might really be a lot smaller, or a lot bigger!

Number of Animal Species

    Another reason it's complicated to estimate the number of animals is because first you have to decide what things are animals. For example, everyone knows a dog is an animal. But what about a flea? Are fleas animals too? (By the way, the answer is yes. Fleas and other parasites are considered to be animals.) 

    Experts can't decide on how many different types of animals there are.  Some experts think there are about 2 million species, but other experts think there may be up to 50 million animal species or more. 

    The marine ecologist Dr. Camilo Mora from the University of Hawaii estimates that there are about 8.7 million species of animals on Earth.

    The easier question to answer is, "How many animal species have already been discovered in the world?" To date, scientists have discovered over 1,200,000 animal species!

Why Haven’t We Discovered All the Species?

    The reason we haven't discovered all of the different species is because some animals are too small or too well hidden to be easily found. Also, some animals may live in places that are hard to get to. Obviously, it’s also a lot harder for scientists to find animals underwater, so this explains why there are probably a lot more sea animals than land animals that have not yet been discovered. So it is unknown how many animal species we haven't actually discovered yet.

Challenges of Counting Animals

      Since some animals are too small to be easily found, and others live in places that curious scientists can't travel to, instead of counting exactly how many animals there are, scientists must make estimates to make a smart guess about the total number of animals. Since estimates are used, we don't really know the exact true number.

Number of Insects

    It's impossible to count every single bug. I couldn't even count how many bugs live in my backyard, let alone the entire planet.

     So estimates based on samples are all that is available for the entire planet. According to the Entomological Society of America, the biologist Dr. E.O. Wilson from Harvard estimates there are 10 quintillion living insects. So that means most of the animals in the world are insects!!!!

Conclusion

     The estimated total number of animals living on Earth is 20 quintillion, and most of those animals are insects. 

     But is 20 quintillion a good guess or a bad guess? It's hard to know for sure. Some experts think that 91% of sea animals and 86% of land animals have not even been discovered yet.  So maybe the real number is much bigger or smaller than 20 quintillion.

     I know this information because I read articles and became more knowledgeable about animals. If you are reading this now  you are more knowledgeable about animals as well. So if your friends and family like animals share this with them.