In the Netflix movie "Leave the World Behind," various symbols are used to convey the themes and underlying messages of the story. One of the most notable symbols in the film is the presence of deer.

1. Deer Symbolism: The deer in "Leave the World Behind" play a significant role in symbolizing the unfolding environmental disaster and the characters' reactions to it. Initially seen as a good omen by Clay, based on Mesoamerican mythology, the deer's presence becomes increasingly ominous as their numbers grow throughout the movie. Their behavior is explained as a response to a catastrophic environmental disaster impacting animal migration patterns. This aligns with Rose's perception that the deer are warning of impending disaster, which is later proven true. The increasing number of deer throughout the film mirrors the escalating disasters and chaos, symbolizing the characters' growing panic and disintegration of their lives amid these events. By the end of the film, the deer become more aggressive, signifying the world's brink of collapse and the limits of their adaptability in finding a new home​.

2. Mystery and Uncertainty: The film leaves many questions unanswered, particularly regarding who is behind the attacks that lead to the crisis. This uncertainty is a key theme, reflecting real-world situations where the true cause of a disaster might not be immediately known. The speculation about different countries being responsible for the attacks and the general state of confusion add to the film's atmosphere of fear and uncertainty. The film plays on this fear of the unknown, showing how lack of knowledge can lead to mistrust and further complications​.

3. Self as Enemy: A philosophical theme in the movie, inspired by Friedrich Nietzsche's idea that one's worst enemy is oneself, is explored. The film suggests that in times of crisis, people may become their own worst enemies. This is depicted through the characters' interactions, where mistrust and self-preservation take precedence over collective problem-solving and cooperation. The families' reluctance to share information with each other despite being in the same predicament illustrates this theme of self-imposed isolation and conflict​.

4. Trust and Control: The film explores the theme of trust and control in extreme situations. As the crisis unfolds, the characters struggle with whom to trust and how much information to share, reflecting a natural human tendency to grasp at any remaining control in chaotic circumstances. This theme is particularly evident in Amanda's suspicion of George and Ruth, and in the families' general approach to survival, where they prioritize their own needs over collective action​.

5. Escapism: Rose's character embodies the theme of escapism. While the other characters are consumed with understanding and responding to the crisis, Rose detaches from reality and finds solace in watching her favorite show, "Friends." This act of escapism is significant as it contrasts with the others' inability to move beyond the immediate crisis. Rose's actions represent a poetic form of escapism, highlighting her unique perspective and response to the unfolding events​.

In summary, "Leave the World Behind" uses symbols like the deer and themes such as mystery, self-enmity, trust, control, and escapism to convey its narrative about human behavior and response in the face of an apocalyptic crisis. These elements together create a rich tapestry of meaning that encourages viewers to reflect on broader societal issues and personal reactions to extreme situations.