And when [Bear] lay dead, of no wound or grief, but stricken by age, the Elder saw for the first time the swift waning of the life of Men, and the death of weariness which they knew not in themselves; and they grieved greatly for the loss of their friends. But Bear at the last had relinquished his life willingly and passed in peace; and the Elder wondered much at the strange fate of Men, for in all their lore there was no account of it, and its end was hidden from them.

The Silmarillion