History of the species
Scientifically, the yellow-eyed penguin is very special. It is the only one in its genus, Megadyptes antipodes.
Penguin fossils dating back more than 60 million years have been found in New Zealand. The yellow-eyed penguin is truly a unique and ancient bird. Recent research has, however, revealed the existence of a now-extinct sister species, known as Megadyptes waitaha. The waitaha penguin was found on the South Island and appears to have been harvested to extinction by Maori around 1500 AD. Yellow-eyed penguins took advantage of the newly available habitat and colonised the mainland from the subantarctic Auckland and Campbell Islands.
Penguins are believed to have evolved at least 65 million years ago from the same ancestral stock as the albatrosses, shearwaters and petrels. Of the 32 fossil penguin species known to science, 16 have been recorded in New Zealand. Many of the ancient penguins were much bigger than their present day descendants, averaging 90 cm in height (contrasted with 60 cm for today’s penguins).
The largest know fossil penguin, Anthropornis nordenskjoeldi, found on Seymour Island in Antarctica, stood 170 cm tall. Pachydyptes ponderosus, found near Oamaru in New Zealand, stood 164 cm tall.
Another giant penguin which lived on New Zealand shores was the Kairuku grebneffi, which stood 130cm tall. Kairuku, a Maori word loosely translated as “diver who returns with food”, probably became extinct from its New Zealand habitat between 24 and 25 million years ago. Kairuku stood 1.3 metres tall – 30 cm taller than its nearest modern-day rival, the Emperor Penguin, of Antarctica. With its spear-like bill, it weighed at least 60 kilograms, which is 50% heavier than the Emperor Penguin.
Researchers are not sure why the "giant" penguins disappeared. Climate change, or increased predation from dolphins and seals, has been suggested as possible causes of extinction.