Giraffe have two types of neck the first type of neck is a short neck and the other type of neck is a long neck. This mean the not all giraffe are the same they have different types of neck.
The giraffe only could have a single baby at a year because the baby have to be on the mother stomach for 425-465 days = 15 months. The giraffe do not have a struggle to give birth, the giraffe give birth standing up, in 20 minutes after the birth the mother could walk perfectly.
The giraffe and the baby are always together, but when a predator is coming closed they are in alert and they start running with the baby, what do giraffe want to do is to protect the baby from the predators the giraffe doesn't want that the lion eat there baby.
Increase: the giraffe have to be alert from predators, and save the baby. Decrease: the giraffe not always could protect there baby the predators could cash the baby very easy.