Yet another alternate theory. Hey, it could be true. Who knows what Gollum was up to in his centuries underground?
The Race that Gollum Bred
Deep below the human world
Sheltered from the sun
There lies in tranquil darkness
A secret known to none
In humid limestone caverns
Dwell the race that Gollum bred
Who swim in silent waters
On eyeless fish are fed
Lithe and razor-fanged are they
With feet like fishes' fins
Emerald are their glowing eyes
Ashen are their skins
They sleep and sing and prowl
Their children grow and play
Living long, contented lives
Not knowing night or day
They carry on the legacy
Of glories now long dead
Male and maiden, mother, babe
The race that Gollum bred