Is there a current population calculation of the number of living animals?

Answer 1

Any estimate is going to be a wild guess. There are, perhaps, a million species of insect alone. Populations of some species run into billions - there are 6 billion humans for a start. Think of a huge number and that will probably be as close as anyone else's huge number.

Answer 2

Any guess would be off by an unknown order of magnitude. That is, there's no way to know. When people hear the word "animals" they usually think of vertebrates, or at least animals large enough to see with the naked eye (insects, little sea creatures, what have you). But then there are tons of other creatures we always forget about. Just take parasites as an example; there are tons and tons of parasites in many living creatures. That means to get any decent calculation, you'd have to count the animals in a population, get an accurate average of the number of parasites each animal has, and repeat the process for every population of animals everywhere. Sounds tough.