Penguins are adorable – their tuxedo plumage, their precious waddle with their little vestigial wings balancing them, their charming fluffy chicks resting on daddy's scaly clawed feet. You look down at them and smile.

Now imagine one looking down at you. Wonder if he'd think you were cute. Fossil penguins that was nearly seven feet long and almost certainly taller than you have been discovered on the Antarctic Peninsula by Argentine paleontologists, who dubbed the extinct bird 'Colossus' by virtue of its awesome proportions.

More formally known as Palaeeudyptes klekowskii, it is the largest-known penguin ever to have walked the earth.

It bears elaboration that penguins aren't measured by "height," but by "length," because of their posture. Their height is somewhat lesser than their length from beak-tip to toes. In the case of Colossus, its beak was mighty long. But unless you're NBA material, it towered over you.

Experts had known that giant penguins had existed, says paleontologist Carolina Acosta Hospitaleche, who works at the La Plata Museum. They just hadn't thought they got that big.

The breakthrough was when Acosta Hospitaleche found an astonishingly large tarsometatarsus - a fused ankle-foot bone - that spanned 9.1 centimeters on Seymour Island. It was the biggest ever found, and from it she extrapolated that the bird was a hair over two meters long, from beak-tip to toe.

The biggest contemporary penguin is the Emperor, which is pretty hefty – it can max out at a height of 130 centimeters. Colossus was three feet taller and weighed twice as much as the Emperor, around 250 pounds, say the scientists.

Sad to say it went extinct some 35 million years ago, a time when the region was somewhat warmer, rather like the tip of South America today. The Colossus was one of many species – about ten, or 14, depending on classifications by squabbling paleontologists - of penguin on Seymour Island.

Modern-day penguins swim beautifully but Colossus had stamina that beat the lot, able to stay underwater for 40 minutes at a stretch, says the team from Argentina's Museum of Natural Science. Yet they went extinct.

All of this begs a question about latter-day penguins. The birds are famous for preferring cold climes. What will happen to them in the changing, warmer world? Some scientists believe they may survive through adaptation, based on evidence that colonies thought to have disappeared had actually simply upped and moved.

Open gallery view An Emperor penguin that got lost and wound up on a beach in New Zealand. Credit: AP