History of the yellow-eyed penguin / hoiho species
Scientifically, the yellow-eyed penguin / hoiho (Megadyptes antipodes) is very special. It is the only species left in its genus, and is truly a unique bird. It may also be the most ancient of all living penguins.
Research revealed the existence of a now-extinct sister species, Megadyptes waitaha. The waitaha penguin was found on the South Island and appears to have been harvested to extinction by Māori around 1500 AD. Hoiho took advantage of the newly available habitat and colonised the mainland from the subantarctic Auckland Islands and Campbell Islands.
Penguins are believed to have evolved at least 62 million years ago, shortly after most of the dinosaurs went extinct. The oldest known penguin fossil is from Waimanu manneringi and was found in North Canterbury in New Zealand. Of the 30+ fossil penguin species known to science, more than half have been recorded in New Zealand. Waimanu literally means “water bird” in Te Reo.
Many of the ancient penguins were much bigger than their present day descendants, averaging 90 cm in height (compared to 60 cm for modern penguins).Complete fossil skeletons are rare, so scientists often have to use the available bones and then fill in the gaps to work out how tall penguins were.
The largest know fossil penguin, Anthropornis nordenskjoeldi, found on Seymour Island in Antarctica, stood approximately 170 cm tall. The New Zealand giant penguin (Pachydyptes ponderosus) and another giant penguin, Kairuku grebneffi found in South Canterbury were slightly smaller. At approximately 130 cm they are taller than their nearest modern-day rival, the emperor penguin. The New Zealand penguin was very robust and weighed about 80 kg (twice the weight of the emperor penguin). Kairuku had a spear-like bill and the name loosely translates from Māori as “diver who returns with food”,
Kairuku probably became extinct between 24 and 25 million years ago. Researchers are not sure why the “giant” penguins disappeared. Climate change, or increased predation from dolphins and seals, have been suggested as possible causes of extinction.