Giraffes are similar to horses, donkeys and mules in their mating method. When the female is receptive and ready to mate, she stands still and allows the male to approach her. He mounts her from the rear, with both female and male facing in the same direction, and inserts his penis into her vagina. When mating ends, he withdraws and backs away. The timing of mating is wholly dependent on when the female is ready and willing.
The Female Cycle
The female reproductive cycle doesn't have any relationship to season – so the species can mate at any time of year. Female giraffes go into estrus, when they ovulate, every two weeks year round. When this happens, she produces chemicals called pheromones that send strong signals to males, letting them know she's ready. Male giraffes spend much of their time wandering in search of these tantalizing scents.
Finding a Mate
When a male giraffe finds a female giraffe in estrus, he nudges her rear end with his nose to encourage her to urinate. The male tastes the urine, checking for signals that she's ready to mate. If things look promising, he follows the female around until she stands still, indicating that the time is right. Occasionally, the male might be anxious and try too soon, but the female just walks away until she's made a positive decision. Sometimes this goes on for hours or even days, and occasionally nothing happens until another, more desirable male appears. She may go up to the new arrival and rub her neck on his, indicating her preference. Often a female giraffe chooses the most dominant giraffe available as a partner, possibly helping strengthening the genes passed to her young.
If the female giraffe conceives, her pregnancy lasts for about 14 1/2 months. She gives birth to her baby standing up, so the newborn's first experience is to fall the long distance to the ground as it leaves its mother's womb. The baby giraffe quickly recovers from this tumble and is up and walking around within an hour. Because the male giraffe leaves after mating, the job of raising and caring for the new baby giraffe falls to the mother.