Great auk (Pen Gwyn in Welsh), or, because the great auk had such large white circles on its head. When European explorers discovered what today are known as penguins in the Southern Hemisphere, they noticed their similar appearance to the great auk and named them after this bird, although biologically, they are not closely related. Whalers also lumped the northern and southern birds together under the common name "woggins". Standing about tall and weighing approximately as adult birds, the flightless great auk was the second-largest member of both its family and the order Charadriiformes, surpassed only by the mancalline "Miomancalla". The great
Ratite as a whole probably had an origin in the northern hemisphere. Early Cenozoic northern hemisphere paleognaths such as "Lithornis", "Pseudocrypturus", "Paracathartes" and "Palaeotis" appear to be the most basal members of the clade. The various ratite lineages were probably descended from flying ancestors that colonised the south in multiple waves, probably initially in South America, and then evolved gigantism. Loss of flight allows birds to eliminate the energetic cost of maintaining flight-enabling pectoral muscle mass. The basal metabolic rate of volant species is much higher than that of flightless terrestrial birds. But energetic efficiency can only help explain the loss