[calf]

https://www.bbc.com/news/science-environment-44412495

And while that's only one animal species, because they're so numerous, the 40 Humboldt penguins, 62 million chickens, rampant rabbits and even the 371,191,500 honey bees pale in comparison, so we can use that as a ballpark estimate for all the animal species as a whole.

There are believed to be around 7.7 million known species of animal on the planet and the National Oceanic and Atmospheric Administration estimates that as much as 95% of the ocean and 99% of the ocean floor has been left unexplored.

So - until we know and have studied all of the species on Earth - this question will remain unsolved.