The remains of a 154 kg (!) heavy penguin discovered in New Zealand

Meet Kumimanu fordycei: the largest penguin – to our knowledge – that has ever lived.

Emperor penguins are not little guys. Measuring over a meter in length and weighing between 22 and 45 kilograms, they are the largest and heaviest of all living penguins. Yet they must have been very disappointed Kumimanu fordycei, a newly discovered penguin species unearthed in New Zealand. Because this “monster penguin” would have weighed no less than 150 kilos!

Discovery
Researchers have found the giant penguin’s fossilized remains in ancient beach rocks in North Otago, located on New Zealand’s South Island. They suspect the remains are between 55 and 60 million years old, which means that Kumimanu fordycei walked the earth some five to ten million years after the extinction of the dinosaurs.

The greatest of all time
The team used laser scanners to create digital models of the bones so they could compare them to the bones of other fossil species and modern penguins. For the height and weight of Kumimanu fordycei to estimate, the researchers measured hundreds of living penguin bones. This led to the astonishing conclusion that it was a truly gigantic specimen, which must have weighed no less than three heads above modern penguins and weighed around 154 kilograms. This makes it – to our knowledge – the largest penguin that has ever lived.

The researchers are amazed at their discovery. “Fossils provide us with evidence for the history of life,” said researcher Daniel Field. “And sometimes that turns out to be really surprising.”

Earlier discoveries
This is not the first time that New Zealand researchers have discovered the remains of a giant penguin. For example, in 2019 they excavated the remains of C. waiparensis; a 1.60 tall penguin that weighed around 70-80 kilograms. And two years earlier, the remains of a gigantic penguin were also discovered, which must have been 1.70 meters tall and weigh around 100 kilograms. This means that New Zealand is apparently littered with the remains of monster penguins. “Many early penguins grew to enormous sizes, which the largest penguins alive today have almost nothing to do with,” says Field.

For what?
A pressing question is why these seabirds have grown so fat at the seams. “Maybe it proved useful in the water,” speculates researcher Daniel Ksepka. “When you grow up, it brings a lot of benefits. For example, a larger animal can catch larger prey. But more importantly, it made it easier for them to maintain their own body temperature in cold water. It’s entirely possible that these big, heavy penguins have spread from New Zealand to other parts of the world.

Petradyptes stonehousei
In addition to the remains of Kumimanu fordyceiresearchers also excavated the remains of another unknown penguin species, they write in Journal of Paleontology. This penguin, whose name is Petradyptes stonehousei received, with a weight of about fifty kilos, is much smaller than Kumimanu fordyceibut still several times larger than today’s emperor penguin.

Evolution
The two recently discovered penguins shed light on the evolution of these animals over time. Thus, they are probably among the first penguins. The team notes that both species possess primitive characteristics, including thin fin bones and muscle attachment points similar to those found in flying birds. The enormous size of the two penguins also shows that gigantism evolved early in the penguin line.

Why penguins became extinct is currently an unsolved case. Researchers hope to learn more about these special birds in the future. “Kumimanu fordycei must have been an extraordinary sight on the beaches of New Zealand 57 million years ago,” says Field. “The combination of its enormous size and the incomplete nature of its fossil remains makes it one of the most intriguing fossil birds ever discovered. Hopefully, future fossil discoveries will shed more light on the biology of this amazing early penguin.