Q. Generally how does a male animal realize that the female is receptive to copulation?

In most vertebrate species with internal fecundation the females have reproductive cycles with fertile periods during this period the female secretes pheromones odoriferous substances that attract the male of the species from the mucosae and skin. The presence of the male individual and his pheromones as well stimulates the release of pheromones by the female. Many animals also use pheromones for signal transmission and for territorial demarcation between individuals about the location of dangers and food.