Kiwi Bird - Largest Eggs In Proportion To Its Size

The chicken-sized species that make up the kiwi family Apterygidae exhibit many unusual traits. The wings are tiny and hidden within the soft, hairlike, gray-brown plumage, and the nostrils are located at the tip of the long flexible bill (rather than at the base, as with most birds). The legs are stout and muscular, with a large claw on each of the four toes. Kiwi are solitary and nocturnal; they live in the forests of New Zealand, sleeping in burrows during the day and foraging at night for worms, insects, and berries.

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.

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