Penguin in 18: Wings become flippers

The tight thermoregulatory huddle is an emperor (and some king) story. Burrowing little penguins and tree-nesting gentoos use different heat tricks. Yes on a decadal clock. Purse-seine competition and shifting sardine/anchovy biomass cut South African colonies by large fractions since the 1950s peak.

Salt glands above the eye dump NaCl as a concentrated drip from the bill — the same avian gadget albatrosses use. Erect-crested and others depend on stable subantarctic fisheries and nest sites. Mice on Gough and other islands add a predation problem flightless birds cannot fly away from.

Penguin is one of 24 types in this animals atlas. The pages treat it as a full system -- history, anatomy, operating principles, culture, icons, future pressure and market shape -- not a ranking of a best species. Scores compare the penguin with the other 23 types on speed, intelligence, range, resilience, cultural impact and ecological role. They are relative editorial marks. Resilience high means more secure; low means threatened. African and several crested penguins are Endangered; emperors were uplisted as climate models tightened.