After Jesus was resurrected, he met with many, his disciples in particular. In Mark 16 verse 15, he instructs them to “Go ye into all the world and preach the Gospel to every creature”. The term “creature” just doesn’t seem to fit, why not “all mankind”, as creature implies other than Man. Was that passage not translated correctly?
The same Greek word also means creation and several modern translations read “to all creation” instead of “every creature.” It sounds strange to us, but 400 years ago, when the King James was published, people would have understood it to mean “preach the Gospel to everyone”. It’s not meant to imply we should also preach to non-humans.
It sometimes helps to compare King James verses that seem confusing with more modern translations to get a better understanding of what they mean.