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
Yellow-billed loon with other birds on good fishing spots. The female lays two eggs measuring . The eggs are strongly oval, and are a light purple-brown with darker blotches interspersed. This colour camouflages with the soil and vegetation that this bird nests near. Most of the time, although, the egg is not visible due to incubation, which takes around 27 to 29 days. The yellow-billed loon is a specialist fish eater, though it also takes crustaceans, molluscs and annelids, especially for its young. It dives in pursuit of prey, which is caught underwater. Probably as a way to avoid spreading parasites, it