Ecclesiastes 3:18-21, and 12:7
I also said to myself, "As for humans, God tests them so that they may see that they are like the animals. Surely the fate of human beings is like that of the animals; the same fate awaits them both: As one dies, so dies the other. All have the same breath (spirit of physical life); humans have no advantage over animals [in this respect]. Everything is meaningless. All go to the same place; all came from dust, and to dust all return. Who knows if the human spirit rises upward and if the spirit of the animal goes down into the Earth?"
And the dust returns to the ground it came from and the spirit returns to God Who gave it.
We see here that all living things have a spirit of physical life (breath) that leaves the body at death, leaving the body dead, to decay into the dust from which it was originally taken at Creation.
And we see that the spirit of Man returns to God Who gave it (when He breathed the breath of life into Adam, and Adam became a living being, Genesis 2:7). So we also see here that the spirit of life in the animal most likely returns to the Earth.
Solomon could not see past death, but he still, in his wisdom, came to the right conclusion.
Even so, come, Lord Jesus!
