I also found the dragons intriguing and wondered about the symbolism. I figured you were onto something about dragons being a symbol of chaos, Thidrek, but I didn't know that I (Fenrir) also had such a high status of evil and chaos in the Norse world view.

Here's an interesting excerpt that discusses the symbolism of dragons and other animals from the essay From Pagan to Christian: The Story in the 12th-Century Tapestry of the Skog Church, Hälsingland, Sweden by by Terje I. Leiren:

Dragons and Other Animals

Just as bells frightened spirits and cleansed the air around a Christian church, dragon heads were placed on the roofs of stave churches to frighten away evil spirits. Although today, animal heads on the stave churches give it a quaint appearance, their use in the architectural structure in the 12th and 13th centuries were, however, very serious business.

In old Icelandic law, it was illegal to bring a ship, with its dragon-head bow, directly into land for fear of offending the spirits of the land. Christian converts did not give up their traditional beliefs in pagan spirits, but instead of protecting and placating the spirits, it was the church and the worshippers inside which now had to be protected. Dragon heads, therefore, served a useful purpose as a part of the church structure. Dragon heads on the church in the Skog Tapestry face out as a protective force for the Christian faith, the faithful and the physical structure of the church itself.

The dragon is only one of a number of animals (real and mythical) in the Viking religious universe. While the dragon is attacking the roots of the Yggdrasil (the World Tree), a squirrel runs up and down carrying insults between the dragon and the eagle in the canopy of the tree.

Most prominently, of course, the Fenris Wolf and the World Snake are two of the representations of evil and chaos itself in the Norse world view. All animals were not evil or threatening. In Christian Scandinavia, the lion, an animal not found in Scandinavia, represents power and royal prestige. In the pagan world, Odin is also associated with animals --his magical horse, Sleipnir, and his two ravens (Hugin and Munin) who served as his "eyes and ears to the world," bringing him news of all developments.