Before mating male giraffes will taste the female’s urine to determine if she would be a good mate.
This is known as the “Flehmen sequence”, where the male giraffe will approach the female and then rub against her backside until she pees. When/if she does, he’ll taste it to tell whether she’s in heat or not. If she is, he will then proceed to stalk her, with the female sometimes continually walking or running away from him. During this time, he will attempt to keep other males away from the female as he pursues her, which is often the point of the female’s rejection, trying to see if she can get a better male to become interested in her and fight off the current male.
When fighting over a female, the giraffes will establish dominance via high or low intensity “necking”. The low intensity version of necking involves pressing their necks against one another until one gets tired and gives up. In high intensity necking, they’ll swing their heads and necks at each other trying to land blows on the other giraffe. This type of fighting can last as much as a half hour before one will concede the match. With either type of “fighting”, very rarely is serious damage done. Further, the one with the longer neck almost always wins.
Somewhat bizarrely, at least from a Darwinian perspective, after a necking battle, the males will often caress one another with their necks (which is sometimes misinterpreted as fighting) and then have sex with each other, including reaching climax. In fact, it’s estimated that 75% to 94% of the time male giraffes have sex, it is with another male giraffe. Although much more rare, female giraffes also occasionally get in on the one gender lovin’ with about 1% of female giraffe sexual encounters occurring between two females, rather than a male/female pairing.
When male and female giraffes do pair up, females tend to prefer older males, usually at least over seven years old, even though the males become mature just four or five years after being born. In contrast, the males tend to prefer the younger females, with these females also becoming sexually mature around four years old.
If the female is particularly interested in a certain male, she may even pursue him, rubbing her neck against him to try to get him to rub her rump so she can pee in his mouth. In these cases, she will rarely play hard to get and usually will let him mount fairly quickly if her urine is to his liking.
Once the female stands still long enough to allow the male to mount, coitus is extremely brief, lasting only a few seconds at most, once again proving it’s not the size of the neck, but how you use it.