They found evidence of one in New Zealand, a 60-million-year-old fossil encased in an ultra-hard sedimentary rock. Scientists estimate the bird weighed about 220 lbs (100 kg) and stood just shy of 6 feet (1.77 meters)—pretty hefty for a penguin.
It’s not very often researchers find the remains of humongous penguins from before the Paleocene period, which marked the start of the mass-extinction event that wiped out many non-avian dinosaurs and huge marine reptiles. A few partial giant penguin skeletons have been reported, but they are rare.
In this particular case, it’s taken researchers about a decade to fully examine the fossilized remains found in New Zealand, which proved especially difficult to extract from the tough rock. Still, they told The Guardian that it was one of the tallest penguins to have ever been found. And while they say it likely wasn’t one of the cutest of the flightless birds, Kumimanu biceae may be one of the evolutionary links showing how penguins looked as they lost their ability to fly and transitioned into swimmers, according to research published in the journal Nature.
“One of the notable features of penguin evolution is the occurrence of very large species in the early Cenozoic, whose body size greatly exceeded that of the largest extant penguins,” the study says.
It remains unclear just why that evolution took place. Researchers in the study say that the change might have been influenced by the extinction of predatory dinosaurs—both marine and terrestrial—which created an ecological driver for giant penguins to spend more time hunting in the water.
Those giant penguins died out about 20 million years ago, though, scientists say. That’s about the time marine animals such as toothed whales and seals would have appeared, increasing competition for food.