What strategy involves changing animal reactions through a better understanding of their environment?

The strategy that focuses on changing animal reactions through a better understanding of their environment is behavior modification. This approach involves systematic techniques aimed at altering specific behaviors by identifying the underlying causes and triggers for those behaviors. By understanding how different environmental factors influence an animal’s reactions, veterinarians and animal caregivers can implement changes that promote a more positive and relaxed state, ultimately leading to improved health and well-being for the animal.

While the other options do relate to altering behaviors, they do not specifically focus on the thorough understanding of the animal's environment. Training techniques often emphasize teaching new skills or commands rather than modifying existing behaviors based on environmental interactions. Reinforcement strategies involve rewarding desired behaviors but may not consider the broader environmental context that triggers those behaviors. Habituation is a process where animals become accustomed to a stimulus over time, but it doesn't encompass the comprehensive understanding of their environment needed for behavior modification. Thus, behavior modification stands out as the most holistic and effective strategy for achieving positive change in animal reactions.