Eudyptes chrysolophus, commonly referred to as Macaroni Penguins, are the largest and most abundant species of penguins in the world. They belong to the crested species and are very similar to the Royal penguins. Macaronis are larger than their cousins and they can be easily distinguished by their trademark yellow-orange crest feathers. This species was named in the 18th century by English explorers for their yellow-orange tassels. The tassels resembled the feathers called 'macaronis' on the hats worn by young men. The term was also made popular by the revolutionary war song Yankee Doodle. Inhabitation and Population Macaroni penguins are inhabitants of the Antarctic and sub-Antarctic regions which include South Georgia, Argentina, Kerguelen islands, Heard and McDonald islands, and Isles Crozet. There is an estimated population of 9 million breeding pairs of these penguins and there are around 216 breeding colonies at 50 locations. Appearance Males weigh around 3.3-4 kg while females weigh around 4-4.5 kg. The females appear to be smaller than the males. Their average length would be around 70 cm. Both males and females have a black throat, chin, and head. The yellow-orange crest originates in the center of the forehead and spreads out horizontally backwards. The body and tail appear to be bluish-black initially and turn brownish later. The males have a relatively larger bill which measures 6.1 cm approximately, while the females' bills measure 5.4 cm approximately. Their legs and feet are pink, their eyes are red, and their crests are fully-developed when they are around 3-4 years old. Their old feathers are replaced once every year through the process of 'molting', which takes three to four weeks. Diet These penguins mainly feed on Krill. Occasionally, squids, crustaceans, and fish also form a part of their diet. They are known to be the largest consumers of marine reserves. Their food hunting abilities are best displayed before or after the breeding season, wherein they dive more efficiently and hunt for a longer time. Breeding Breeding takes place in colonies on coasts and cliffs. The males start breeding when they are around six years of age while the females can start breeding at the age of five itself. The population of males is more than that of females. October is a favorable time for breeding and they lay eggs by November. For nesting purposes, they prepare a shallow pit in the ground with stones and tussock grass lining it. Two eggs are laid with a gap of 4-5 days between each, the first weighing around 90-94 grams and the second around 145-155-grams. The first egg has very less chances of surviving. Incubation lasts for about 5 weeks and incubation duties are performed in shifts by the male and female. After the eggs hatch, the chicks are fed for about 24 days until they start showing signs of rapid development. At 11 weeks of age, the chicks fledge and are ready to leave their parents. The parent penguins then leave their breeding colonies and go to sea. They live between 8 to 15 years in the wild. Predators and Threats The Leopard seal, killer whales, and the Antarctic Fur Seal prey on adult macaroni penguins, while the eggs and young ones are preyed upon by the Giant Petrels, the Kelp Gull, and the Skua. They are threatened by the rising temperatures of the sea-surface due to global warming, marine pollution, and commercial fishing. Their species have been declared 'vulnerable' by the IUCN Red List of Threatened Species. Owing to the decline in the population of Macaroni penguins, despite their large numbers, steps are being incorporated to protect their breeding colonies as well as their habitats.