Dream language
Why Toltecs may be the question here? Personally, I have started with these as I had encountered the same archetypes long before I consciously used them for invocation of lucid dreams. I have been keeping a dream diary for more than 10 years and looking back I realised, to my astonishment, that these regularly appeared in my dreams around major themes. The history of lucid dreaming practice is very old and nobody can tell exactly when or where it exactly originated from. The Toltec culture which is more than thousand years old inherited lucid dreaming methods from even older lineages, stemming from times that anthropologists find it hard to pinpoint in time. In ancient Greece dream temples existed for healing purposes. Old Egypt also features symbolism that reflects the connection with the dreaming practices of the Toltec culture, suggesting deeper connection to possibly even older times. In the far east, Tibetan Buddhists have practiced dream yoga with the goal to reach enlightenment, which also represents a complex set of lucid dreaming practices that tend to go even further than the western idea of lucid dreaming.
Why do dreams relate to archetypes?
No matter the history, some more accessible methods are available to everyone which can be integrated more easily with the western way of living and perceiving. Usually, one links a certain goal to the chosen set of animal archetypes and performs the exercise called "dream planting" before going to bed. This essentially boils down to planting seeds of a dream where you assign meaning to a certain animal archetype. When they make appearance in your dream you are able to relate to it better and recognize its meaning.
Why does working with animal archetypes work so well? Many people might deem this strange, especially those who are not into ancient symbolism and may not relate so well to something that does not immediately appeal to the rational mind. The truth is, if one wants to explore the subconscious one has to go past the rational mind in the first place. Besides, we do have animal consciousness deeply ingrained in us as the result of the evolutionary process, so it speaks to the subconscious in the familiar way.
It resembles a high-resolution game!
If pure intention proclamation works better, one can try this as well, I
have played with various options as it can be refreshing to change techniques.
Some of the Buddhist practices involve visualising geometric forms for
instance. However, if you are a beginner in lucid dreaming, starting with
animal archetypes will make your dreams explode with content you are likely to
remember better. Once a role to an archetype is assigned, seeing it in a dream
is an excellent lucidity trigger as well.
In short, you are triggering your subconscious with symbols that it does
understand and it is sending you dream back as an answer.
Do not expect that the dream will always send you the image of an animal, often it will set up a complete 3D immersive scene that revolves around the topic used in the planting process. And, like in a game, one needs to find the way and uncover the dream message behind it. When doing this regularly, by addressing additional goals or refining the existing ones, dreams will eventually show you archetypes designed for you. Once again, it is like playing a game with the dream, yours is to throw the ball and observe what you get back. Keeping the dream diary is essential to be able to recognize recurring themes better and develop own intuition around dream symbolism.