* Constant Discovery: Scientists are constantly discovering new species, meaning the number is always changing.
* Difficult to Count: Many species live in remote or inaccessible areas, making them hard to count.
* Defining Species: There's not always clear consensus on what constitutes a distinct species, particularly with insects and microbes.
However, here are some estimated figures:
* 1.5 million is a rough estimate of the total number of species described by science.
* 8.7 million is an estimate of the total number of eukaryotic species on Earth, with animals comprising a large portion of this.
* Scientists believe that millions, if not billions, of species are still undiscovered.
It's safe to say that the animal kingdom is incredibly diverse and vast!