A meta-analysis and review of risk assessment in animals reveal that factors such as predator speed, size, and directness of approach significantly influence flight initiation distance, a key measure of fear in animals. These factors consistently increase perceived risk, leading to greater flight distances. Conversely, the presence of armor or cryptic coloration reduces perceived risk. However, body temperature in lizards does not significantly affect flight initiation distance. Group size also plays a role, with fish showing reduced flight distances in larger groups, while other species flee at greater distances. Experience with predators increases perceived risk, and prey behavior is sensitive to predator density and sequential approaches. The study highlights the importance of predator behavior in shaping fear responses and the coevolution of predator and prey strategies. It also shows that refuge distance is a major factor in flight decisions, with prey fleeing farther when distant from safety. The results suggest that prey respond to environmental and predator-related cues to minimize risk, and that these responses vary across species. The study underscores the complexity of risk perception in animals and the need for further research into the mechanisms underlying these behaviors.A meta-analysis and review of risk assessment in animals reveal that factors such as predator speed, size, and directness of approach significantly influence flight initiation distance, a key measure of fear in animals. These factors consistently increase perceived risk, leading to greater flight distances. Conversely, the presence of armor or cryptic coloration reduces perceived risk. However, body temperature in lizards does not significantly affect flight initiation distance. Group size also plays a role, with fish showing reduced flight distances in larger groups, while other species flee at greater distances. Experience with predators increases perceived risk, and prey behavior is sensitive to predator density and sequential approaches. The study highlights the importance of predator behavior in shaping fear responses and the coevolution of predator and prey strategies. It also shows that refuge distance is a major factor in flight decisions, with prey fleeing farther when distant from safety. The results suggest that prey respond to environmental and predator-related cues to minimize risk, and that these responses vary across species. The study underscores the complexity of risk perception in animals and the need for further research into the mechanisms underlying these behaviors.