The WTBTS teaches that death in human beings is unnatural and was brought about by Adam eating the fruit of the Tree of Knowledge of good and bad.
They claim that one of the proofs that death is not natural in humans is the reaction of humans when one of their number dies....terrible grief. They claim that animals do not care if one of their number dies. They give the example of sheep in a field who couldn't give two hoots if a fellow sheep dropped dead.
However, the mate of a neighbours dog died a few weeks ago. Its surviving mate has barely eaten since. It whines pitifully and there is no consoling the poor thing. The mate of one of my birds died. She grieved pitifully for weeks and weeks.
Death, as tragic as it is, is natural in all living things.
That it isn't, is just another pathetic Watchtower lie.