Final answer:
Camouflage is the correct answer as it is a physical adaptation rather than a behavioral defense mechanism. Examples such as alarm calling, spatial avoidance, and reduced activity are all behaviors that directly involve actions taken by organisms to avoid predation.
Step-by-step explanation:
The behavioral defense against predation that is NOT listed is camouflage. Behavioral defenses generally involve actions or activities taken by organisms to avoid being preyed upon. The options listed: 1) alarm calling, 2) spatial avoidance, and 4) reduced activity, are all direct behavioral actions. Camouflage, however, is a physical adaptation rather than a behavioral strategy. It falls under the category of cryptic coloration and is used as a passive defense mechanism to help an organism blend with its surroundings, making it harder for predators to detect. The false alarm calls mentioned in ethology can be an example of deceptive behavior, which is a behavioral adaptation to increase an organism's chance of survival or access to resources, like food.