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
Crotophaginae Crotophaginae The Crotophaginae are a small subfamily, within the cuckoo family Cuculidae, of four gregarious bird species occurring in the Americas. They were previously classified as a family Crotophagidae. The subfamily is notable for the development of cooperative breeding where several females lay eggs in a communal nest. It contains the three anis and the guira cuckoo. Among the anis, there is considerable variation in nesting habits. One species, The greater ani "C. major" lays 2 or 3 eggs, while the groove-billed ani "C. sulcirostris" lays seven. However the smooth-billed ani "C. ani" will share one nest between several females,