How many animals are there in the world

How many different animal species are there in the world?

Many animals die out before they are even discovered and scientifically recorded.

Many animals die out before they are even discovered and scientifically recorded. Nobody knows the exact number of species found on earth. The estimates are between five and fifty million, says the head of the Department of Integrative Zoology at the University of Vienna, Andreas Wanninger.

It sounds like a simple question, but in fact, even experts cannot answer it exactly. Earlier estimates suggest that there could be between five and fifty million animal species on earth. Only animals that have a nucleus, i.e. eukaryotes, are counted as animals. Microorganisms such as tiny bacteria or microbes are left out. "Newer computer calculations see a possible range of five to ten million species," says zoologist Wanninger.

The number is extremely difficult to estimate. "Around 10,000 new insects alone are discovered every year," says Wanninger. Experts assume that 90 percent of all species - animals and plants - are and often remain unknown. They die out before they are scientifically described. Ergo, we only know about ten percent of all animal species that cavort around the globe.

According to Wanninger, taxonomy, the science that deals with the description of animals, is all the more important. However, there is less and less financial means for this. Biodiversity, i.e. the biological diversity of the planet, is therefore becoming increasingly poorly recorded, he warns.

Wanninger himself is more fascinated by well-known animals: he researches invertebrate organisms that live in the sea, such as octopuses, mussels and snails. By comparing different groups of animals from the fertilization of the egg to the youth stage, he finds similarities and differences. In this way, relationships between animals can be clarified and a look at their evolutionary history.

Send questions to: [email protected]

("Die Presse", print edition, September 19, 2015)