Penguins are certainly one of the more cute and charismatic of the Antarctic fauna, but would people be so fond of penguins if they were over 2 metres tall? Fossils recently unearthed in Antarctica have revealed that giant penguins used to roam this icy continent.

Palaeeudyptes klekowskii, discovered on Seymour island off the Antarctic peninsula, was a penguin weighing 115 kilograms and towering above most people at 2m (6ft7). That’s two and a half times heavier, and nearly twice the height of an Emperor penguin (Aptenodytes forsteri)!

Based on the sedimentary rocks the fossils have been found in, scientists have estimated P. klekowskii lived around 37 – 40 million years ago. This was the golden age of penguins, with at least 10 different species roaming the Antarctic coast. The climate was warmer at this time, and Seymour island would have seemed more like modern day Tierra del Fuego. This site has been particularly fruitful for fossilised penguin remains, and several partial P. klekowskii skeletons have been found here.

The most recent find, published this month in Comptes Rendus Palevol, included two enormous bones – a wing bone and a tarsometatarsus, a fusion of the ankle and foot bones. The tarsometatarsus was over 9 cm long, suggesting the bird measured over 2 meters from beak to toes. Because of the way penguins stand, they tend to be longer in water than they are tall on land, losing a few centimeters through their hunched stance. So, P. klekowski may have been eye-level with a 5ft11 human. It would still have been taller than me, though!

Larger penguins are able to dive deeper and longer. If P. klekowski was as tall as the estimates suggest, it could have dived for 40 minutes, and potentially caught more or larger fish.

Dr Dan Ksepka from the Bruce Museum in Greenwich told New Scientist that the bone is the “longest foot bone I’ve ever seen. This is definitely a big penguin”. However, he warned that estimates of the total size of the extinct penguin is difficult because giant penguin skeletons were “very differently proportioned than living penguins”.

P. klekoewskii wasn’t the only giant penguin wandering around during the warmer Eocene and Oligocene periods; the fossilised remains of Inkayacu paracasensis, found in Peru in 2010 indicate that it was almost 1.5m tall. And in 2012, scientists finally pieced together the puzzle of fossilised penguin bones found 35 years ago in New Zealand, known as Kairuku. This bird stood at around 1.3m tall and lived around 27 million years ago on the small area of land in New Zealand that was not covered by the higher seas of the Oligosene.

The remains of I. paracasensis came with a few fossilised feathers that revealed an interesting phenomenon; giant penguins don’t have giant feathers. It’s feathers were fairly average-sized compared to modern-day penguins, and there are several much smaller living species of penguin that have larger feathers than I. paracasensis! This ancient penguin also looked a bit different, with grey feathers rather than the tuxedo-look that modern penguins have gone for. The fossils of P. klekowskii discovered so far don’t give us many hints as to what they may have looked like, and so far no feathers have been discovered. The best we can at the moment is: “think Emperor penguin but much, MUCH bigger”.

Want to Know More?

• Hopsitaleche (2014) New giant penguin bones from Antarctica: Systematic and paleobiological significanceComptes Rendus Palevol
• Hopsitaleche & Reguero (2014) Palaeeudyptes klekowskii, the best-preserved penguin skeleton from the Eocene–Oligocene of Antarctica: Taxonomic and evolutionary remarksGeobios
• Clarke et al (2010) Fossil Evidence for Evolution of the Shape and Color of Penguin FeathersScience