Which hormone can attract a male dog from over a mile away?

Estrogen is the hormone responsible for attracting male dogs from a significant distance, such as over a mile away. This is particularly important during a female dog's heat cycle, known as estrus. During this time, the levels of estrogen rise, creating scents that signal her reproductive status to male dogs. The olfactory system of dogs is extremely sensitive, allowing them to detect these pheromones from great distances, which is crucial for reproductive purposes.

In contrast, progesterone is primarily involved in preparing and maintaining the uterus for pregnancy rather than attracting males. Testosterone, while important for male characteristics and reproductive behaviors, does not function in the same way as estrogen when it comes to attracting mates. Norepinephrine is a neurotransmitter involved in stress and alertness, not reproduction, and does not play a role in attracting males. Understanding the specific roles of these hormones highlights why estrogen is the correct choice when it comes to attracting male dogs.