The age at sexual maturity in the female giraffe G. camelopardalis was found to be 3 years 10 months when in captivity and 4 years 8 months in wild animals. The mean calving interval was 19.9 months for wild animals, and 21.5 months for captives. Post partum intervals as short as 19, 23 and 27 days until the next conception were recorded. Giraffe are polyestrous and monotocous, but one record of stillborn twins from the eastern Transvaal, South Africa (the first certain case of twins in the wild) is reported. The placenta is polycotyledonous and of the syndesmochorial type. Implanatation occurs on the same side as the corpus luteum of pregnancy and embryonic development can proceed without attachment for at least 30 days. Reproductive activity does not cease in females of advanced age.