Largest penguin species ever

The largest penguin species ever is the Antarctic giant penguin (Palaeeudyptes klekowskii), aka "Mega Penguin", which is estimated to have stood up to 2 m (6 ft 6 in) in height and weighed as much as 115 kg (254 lb). It lived in Antarctica's Seymour Island approximately 37 million years ago, during the Late Eocene epoch.

This is taller than the previous record holder, Nordenskjoeld's giant penguin (Anthropornis nordenskjoeldi), which stood 1.7 m (5 ft 7 in) tall and also existed during the Eocene epoch, occurring in New Zealand and in Antarctica's Seymour Island.

Meanwhile, the heaviest species of penguin ever recorded is a recently described prehistoric species, Kumimanu fordycei, known from fossil remains discovered inside boulders in North Otago, on New Zealand's South Island. By comparing the size and density of its bones with those of modern-day penguins, researchers estimate that it weighed 154 kg (340 lb), which is three times that of today's largest species, the emperor penguin (Aptenodytes forsteri). The rocks containing the remains of this new giant fossil species date between 55.5 million years and 59.5 million years old, meaning that it existed during the Late Palaeocene. Details of the record-breaking prehistoric penguin were published in the Journal of Paleontology on 8 February 2023.