Attract Potential Mates
The chief reason an organism, generally a male, displays courtship behavior is to attract a female to mate with. Many species of male birds, for example, will sing intricate songs to advertise their availability and showcase their healthiness. Dancing and other physical displays are used to tempt potential partners. The gypsy moth releases pheromones that can be detected by male moths miles away. Turtles, on the other hand, depend on actual touch to court a female.
Recognize Mates
Courtship behavior not only attracts mates, but also allows potential mating candidates to recognize an appropriate mating possibility. Mating rituals allow members of the same species to recognize each other, preventing inter-species breeding that does not produce viable offspring. It is also a way for one member of the pair, usually the male, to demonstrate his healthiness and strength. This allows the female to choose the best mate, which will in turn give her offspring the best chance of survival.
Establish Bond
Courtship behavior also allows a mating pair to establish a bond. This is important to their success in raising offspring, and particularly consequential to animals that will mate for life, such as many types of birds. In some species, like boobies, a female bird will join the male in his elaborate dance. Some females will respond to a male's singing by joining in as a duet. Other bird species will preen each other to help dissolve spatial boundaries and aggression.
Courtship Behavior in Humans
Modern courtship behavior in humans is commonly called "dating," but fulfills many of the same purposes as it does in the animal kingdom. Although it varies among cultures, both partners will engage in social activities as a way of evaluating the other person and building a bond. In the most general sense, courtship eventually leads to the decision if an engagement or marriage will take place. The couple will determine if they are compatible, and perhaps eventually suited to have children with each other.