How Many Animal Species Are There in the World?

Have you ever wondered how many different kinds of animals live on our planet? The answer is not so simple, because there are many ways to define what an animal is, and how to count them. In this blog post, we will explore some of the estimates and methods that scientists use to answer this question.

One way to estimate the number of animal species is to look at how many have been formally identified and cataloged by humans. According to Livestocking¹, there are currently around 8.7 million species of animals in the world, but only around 1.3 million have been named and described². This means that there are still millions of animal species that are unknown or undiscovered by us.

Another way to estimate the number of animal species is to look at how they are classified into different groups based on their characteristics and evolutionary relationships. For example, animals can be divided into two major groups: vertebrates (animals with backbones) and invertebrates (animals without backbones). According to ThoughtCo³, invertebrates make up about 97% of all known animal species, while vertebrates make up only about 3%. Within these groups, there are further subdivisions based on more specific features, such as body symmetry, skeleton type, body segmentation, appendages, etc.

However, both of these methods have limitations and uncertainties. For one thing, not all regions of the world have been equally explored and studied for their biodiversity. Some habitats, such as tropical rainforests or deep oceans, may harbor more undiscovered species than others. For another thing, not all species are easy to identify or distinguish from each other. Some may look very similar but have different genetic makeup or behavior. Some may vary depending on environmental conditions or life stages. Some may even interbreed with other species and produce hybrids.

Therefore, it is impossible to give a precise number for how many animal species there are in the world. The best we can do is to use various methods and sources of data to make reasonable estimates based on our current knowledge and assumptions. As we learn more about the diversity and complexity of life on Earth, we may revise our estimates accordingly.