Which Bird Lays the Biggest Egg?
The ostrich, the world’s largest bird, lays the biggest egg. This egg is about the size of a large grapefruit, and its shell could hold about 19 chicken eggs.
The largest egg on record weighed 2.589 kg (5 lb 11.36 oz) laid by an ostrich (Struthio camelus) at a farm owned by Kerstin and Gunnar Sahlin (Sweden) in Borlänge, Sweden, on 17 May 2008.
If a 250-pound animal sat down on an ostrich egg, the egg would not break – it’s that hard! Getting out is no easy matter for the baby ostrich. Baby ostriches have a hard little knob at the end of their beaks which is called the egg tooth
They use this knob to crack the thick shell of the egg so they can wriggle out. This may require hours or even days. Finally, the chick emerges, already a foot tall. The egg tooth falls off a few days after hatching.
Almost all birds use an egg tooth to break out of their eggs. The only exceptions are the megapodes, a group of large chicken-like birds from Australasia, and the kiwi, both of which kick their way out instead.
In terms of relative size, the kiwi lays the biggest egg. The egg is so large, in fact, that it takes up almost the entirely of the female’s internal cavity.
During the last few days before the egg is laid, the female kiwi cannot eat because there simply isn’t enough room in her body for stomach expansion. When it is finally laid, the egg is a quarter of its mother’s weight – that’s the equivalent of a human mother giving birth to a six-year-old child.