In Michael Crichton's book "Congo," the essence of life is portrayed as a fundamental drive for survival. Animals in their natural habitats are depicted as primarily focused on staying alive, rather than being preoccupied with abstract concepts like beliefs or philosophies. This instinctual behavior is critical for their existence and highlights the primal nature of life forms in the wild.

Crichton emphasizes that when an animal's behavior disconnects from the practical realities necessary for survival, it risks extinction. This observation serves as a reminder of the importance of adapting to one's environment and the consequences of ignoring the basic instinct to live, demonstrating the fragile balance between existence and the dangers posed by ignoring nature's demands.