In comparison with other birds, Kiwi lays the largest eeg in proportion to its body. Kiwi birds lay around 100 eggs during their lifetime. Life expectancy of kiwi is from 50 to 60 years. Below is how an egg sits inside the bird’s skeleton.
The egg is equivalent to 15-25% of the bird’s body mass. To compare, ostrich’s egg is equivalent to 2% of the mother’s body mass, while a newborn human accounts only for 5% of the mother’s body mass.