Description The Chinstrap Penguin (Pygoscelis antarcticus) is a species of penguin which is found in the South Sandwich Islands, Antarctica, the South Orkneys, South Shetland, South Georgia, Bouvet Island and Balleny. Their name derives from the narrow black band under their heads which makes it appear as if they are wearing black helmets, making them one of the most easily identified types of penguin. Other names for them are "Ringed Penguins", "Bearded Penguins", and "Stonecracker Penguins" due to their harsh call. Chinstrap Penguins grow to 68 cm (27 in) in length, and a weight of 6 kg (13.2 lbs); however, their weight can drop as low as 3 kg (6.6 lbs) depending on the breeding cycle. Males are both larger and heavier than females. The adult Chinstraps' flippers are black, with a white edge. The inner sides of the flippers are white. The face is white extending behind the eyes. The chin and throat are white as well. The short bill is black. The eyes are reddish-brown. The strong legs and the webbed feet are pink. The chinstrap penguin is able to withstand swimming in freezing waters due to its tightly packed feathers, which provide a waterproof coat. Thick blubber deposits provide insulation as well, and blood vessels in the flippers and legs have evolved intricate structures to preserve heat. The chinstrap penguin's black-and-white plumage helps camouflage it in the water from predators, such as seals. When seen from above, the bird's black back blends into the dark water below, while the bird's underside blends into the sunshine above when seen from below. There are 12 - 13 million chinstrap penguins. They have an average life span of 15-20 years. Chinstrap Penguins are considered the most aggressive penguin. Habitat They live on barren islands and large icebergs of the sub-Antarctic Region and the Antarctic Peninsula; however, they generally require solid, snow-free ground to nest on. The Chinstrap Penguin's primary predator is the leopard seal. There are 12 - 13 million chinstrap penguins. They have an average life span of 15-20 years. Breeding On land (and occasionally on icebergs) they build circular nests from stones, and lay two eggs, which are incubated by both the male and the female for shifts of 6 days. The chicks hatch after about 37 days, and have fluffy gray backs and white fronts. The chicks stay in the nest for 20–30 days before they go to join a creche. At around 50–60 days old, they moult, gaining their adult feathers and go to sea. Diet Their diet consists of krill, shrimp and fish, for which they swim up to 80 km (50 mi) offshore each day. Threats The predator of adult Chinstraps is the Leopard seal. Eggs and chicks can fall prey to birds, such as sheathbills and the Brown skua.