Horse reproduction begins with courtship and ends with fertilization. The male, known as the stallion, detects the female's readiness for mating through scent. As the female, or mare, accepts his advances, the stallion mounts her back and uses his sexual organ, called the penis, to deposit sperm into the mare's reproductive tract. Fertilization takes place when the sperm meets the egg, and, if successful, the mare will carry the developing foal for approximately eleven months before giving birth.