Kiwi eggs are huge with respect to the size of the mother: the female kiwi lays an egg equivalent to 15–20 percent of her body mass. In contrast, ostrich eggs equal a mere 2 percent of the female ostrich's weight, and a newborn human weighs just 5 percent of its mother's weight at birth.
DNA analyses in 1995 and 2003 redefined the kiwi family structure by identifying five distinct species. These are the North Island brown kiwi (Apteryx mantelli); the little spotted kiwi (A. owenii); the great spotted kiwi (A. haastii); the rowi (A. rowi); and the tokoeka kiwi (A. australis). The latter is further divided into numerous subspecies.