Present in both males and females, but the knob on the male may develop into what looks like a third horn. Forehead becomes more heavily ossified, forming an additional knob in front of main horns. Cartilaginous bumps grow and begin to ossify (become bony) starting at the tip, eventually merging with skull. Horns fully developed at 4-4.5 years in males and 7 years in females. Mal es: about 9-10 years (varies: 8-11 years) (Bercovitch and Berry 2012 Berry and Bercovitch 2012). No difference in behavior or development among subspecies has been reported. Males tend to wander farther, at a younger age, than females. Independent of mother by two years of age, but some association may last longer (especially among females). Weaning age varies (6-17 months), but most commonly begins at 9-12 months (wild giraffe) (Langman 1977). At about 4-6 months, calves begin to feed with the female herd. Reports of calves tasting leaves when only 3 weeks old. Sometimes, a few females stay behind to care for the young, but young can be left alone for several hours. They will return to feed their young before dark and stay through the night. At this time, many mothers will leave for long periods to browse. After 1-4 weeks, calves may begin grouping together in crèches, with mothers standing watch for predators and other dangers. Lions may lunge at nursing females to distract females from their calves (Strauss and Packer 2012). Mother also actively defends calf against predators, like lions. Will often leave the calf alone for several hours at a time, as she travels to water. Mother is often at least 10-25 meters (33-82 ft) away. When too young to defend themselves, calves remain still, lying on the ground, hiding (Toon and Toon 2004). Females give birth alone and remain alone with their calves for a week or more, protecting calves from predators and avoiding other giraffes. Females tend to return to the same calving area for successive births. Colostrum, a first milk after birth, confers immunity from some diseases to a calf. Lactating females produce 2.5-10 liters of milk per day ( Wilson and Mittermeier 2011). Begin suckling within an hour (Dagg 2014). Newborns are able to stand about 5-20 minutes after birth. 
Shoulder height of calf at birth: 1.5-1.8 m (4.9-5.9 ft) ( Wilson and Mittermeier 2011).
Neonate wild giraffe heavier than captive giraffe (Skinner and Hall 1975).Weight of calf at birth: ~100 kg (220 lbs) (wild giraffe) (Skinner and Hall 1975 Wilson and Mittermeier 2011).Not thought to be affected by infant survivorship (Bercovitch and Berry 2009b).Interbirth interval: 19-22 months on average (similar for wild and captive giraffe) (Leuthold and Leuthold 1978 Bercovitch and Berry 2009b Bercovitch and Deacon 2015).Maximum age at last parturition: 24 years old (wild giraffe) (Bercovitch and Berry 2009b Berry and Bercovitch 2012).May be earlier in managed care, possibly due to environmental factors such as diet quality.Age of first parturition: 6-7 years old (wild giraffe) (Bercovitch and Berry 2009b Berry and Bercovitch 2012).Females can become pregnant again while lactating, an unusual trait for large mammals (Bercovitch and Berry 2009b).Possibly nutritional advantages related to season see Lee et al.May be influenced by rainfall, food availability, and other conditions helpful to female giraffe.Births occur throughout the year, though some occur seasonally (Dagg 2014).Breeding occurs throughout the year (Bercovitch and Berry 2009b).
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