Demény István: Dél-Amerika és az Antarktisz-félsziget (2008) / 1060-2008
Whales are classified into two groups - toothed whales, such as dolphins and sperm whales, and baleen whales, such as blue or humpback. Baleen whales have baleen plates hanging from their upper jaws that allow them to filter plankton out of the tons of water they take into their mouths. Plankton, tiny organisms that live in water, are baleen whales' only food source. Penguins The emperor penguin - The largest of the penguins , lays its single egg during the coldest time of the year, when temperatures drop as low as -66 degrees C (-80 degrees F). The egg is incubated on top of the parent's feet, protected by abdominal folds of skin. Young chicks remain here for a short time until they are able to regulate their own body temperature. Penguin, common name for flightless, aquatic birds of the southern hemisphere. The name penguin originally was applied to the now extinct great auk of the North Atlantic, a large flightless, black and white bird with an upright stance. Similar flightless birds were discovered subsequently in the southern hemisphere, and they were also called penguins, a name that is now restricted exclusively to these birds. Penguins usually walk or hop and toboggan along on their breasts, pushing with wings and feet. They swim with great speed and agility. The flippers are their sole means of propulsion; the feet are trailed behind or used in steering. Some species progress by porpoising, which is swimming underwater some distance, emerging in a graceful arc to take a fresh breath, and submerging again. Penguins feed on fish, cuttlefish, crustaceans, and other small sea animals.
