The ostrich. Although it is the largest single cell in nature, an ostrich egg is less than 1½ per cent of the weight of the mother. A wren’s egg, by comparison, is 13 per cent of its weight. The largest egg in comparison with the size of the bird is that of the Little Spotted kiwi. Its egg accounts for 26 per cent of its own weight: the equivalent of a woman giving birth to a six-year-old child.
