As the tree Yggdrasil was ever green, and its leaves never withered, it served as pasturing ground not only for Odin’s goat Heidrun, which supplied the heavenly mead, the drink of the gods, but also for the stags Dain, Dvalin, Duneyr, and Durathor, from whose horns the honeydew dropped down upon the earth and furnished the water for all the rivers in the world.
In the seething caldron Hvergelmir, close by the great tree, was a horrible dragon called Nidhug, which continually gnawed the roots, and was helped in his work of destruction by countless worms, whose aim it was to kill the tree, knowing that its death would be the signal for the downfall of the gods.
“Through all our life a tempter prowls malignant,
The cruel Nidhug from the world below.
He hates that asa-light whose rays benignant
On th’ hero’s brow and glitt’ring sword bright glow.”
Viking Tales of the North (R. B. Anderson).
Scampering continually up and down the branches and trunk of the tree was the squirrel Ratatosk (branch borer), the typical busybody and tale bearer, which passed up and down, reporting the eagle’s remarks to the dragon, and vice versa, in the hope of stirring up strife between them.
Bifröst.
To maintain the tree Yggdrasil in a perfectly healthy condition, the Norns or Fates daily sprinkled it with the holy waters from the Urdar fountain, and as this water trickled down to earth it supplied the bees with honey. From either edge of Nifl-heim, arching high above Midgard, rose the gods’ bridge, Bifröst (Asabru, the rainbow), built of fire, water, and air, whose quivering and changing hues it retained, and over which none but the gods were privileged to travel to and fro, on their journey to the earth or to the Urdar well, at the foot of the ash Yggdrasil, where they daily assembled in council.