There were once giant penguins
The emperor penguin, which may grow to a height of around 4 feet, is the biggest species of penguin still alive. However, 2017 fossil discoveries in New Zealand revealed that the area was formerly home to penguins that were the size of people. They were 5 feet, 10 inches tall, roughly 220 pounds, and lived between 55 and 60 million years ago. The researchers concluded that the discovery of a giant penguin in the Paleocene period "suggests that gigantism in penguins evolved shortly after these birds became flightless divers." Although not the only enormous penguins in prehistoric times, they are the oldest and largest that researchers have so far discovered.
Besides, the Peruvian, Icadyptes Salasi giant stood at a somewhat shorter 5 feet during the same time but further north. This enormous creature had a distinctive 7-inch beak that may have been useful for spearing fish. The finding of this fossil challenged earlier theories of penguin migration to the equatorial region. After episodes of Earth cooling, such as those that happened during the Eocene-Oligocene (about 34 million years ago) and a subsequent cold event 15 million years ago, it was believed that penguins moved northward toward the equator. However, Icadyptes' previous migration shows that penguins did move at a period of substantial warming.
Except for Anthropodyptes Gilli, the majority of the enormous penguins had long since perished by 23 million years ago, during the early Miocene. Even up to 18 million years ago, this behemoth was still thriving in Australia. It is thought that after the extinction of the big penguins, the crested penguins' common progenitors to all living penguins today radiated from an Antarctic ancestor. A common ancestor of all existing penguin species existed as recently as 20 million years ago, according to genetic research of four penguins and discoveries of penguin fossils. Individual present species diverged between 11 and 16 million years ago. The evolutionary history of contemporary penguins is still a subject of active scientific discussion.