Egg embryo is adequately developed it hatches, i.e. breaks out of the egg's shell. Some embryos have a temporary egg tooth they use to crack, pip, or break the eggshell or covering. The largest recorded egg is from a whale shark, and was in size. Whale shark eggs typically hatch within the mother. At and up to , the ostrich egg is the largest egg of any living bird, though the extinct elephant bird and some dinosaurs laid larger eggs. The bee hummingbird produces the smallest known bird egg, which weighs half of a gram (around 0.02 oz). Some eggs laid
Largest prehistoric animals "Argentavis magnificens" which a wingspan of , and a body weight of . The largest-known waterfowl of all time belonged to the Dromornithidae (e.g. "Dromornis stirtoni"). The largest-known of Ciconiiformes was "Leptoptilos robustus", standing tall and weighing an estimated . The largest-known of the hesperornithines was "Canadaga arctica" at long. The largest-known diatryma was "Gastornis" tall, with large individuals up to tall. The largest-known teratorn and the largest flying bird ever was "Argentavis". The immense bird had a wingspan estimated up to and a weight up to . It was as high as an adult human when standing. The largest-known-ever