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
Marine mammal mammals emit loud and noxious underwater sounds. Two changes to the global atmosphere due to anthropogenic activity threaten marine mammals. The first is increases in ultraviolet radiation due to ozone depletion, and this mainly affects the Antarctic and other areas of the southern hemisphere. An increase in ultraviolet radiation has the capacity to decrease phytoplankton abundance, which forms the basis of the food chain in the ocean. The second effect of global climate change is global warming due to increased carbon dioxide levels in the atmosphere. Raised sea levels, sea temperature and changed currents are expected to affect marine mammals