Penguins loom large in pop culture, but they were once even bigger. Several extinct giant penguins, such as human-sized Kumimanu biceae, described in 2017, could have tipped the scales at more than 200 pounds.
Today, their sizes range from the blue penguin, just over a foot tall, to the emperor penguin, nearly three times as big. Regardless of size, all penguins have the same body plan, including wings that have evolved into flippers and dense bones to counter buoyancy.
Hard evidence of the very first penguins is lacking. However, based on a 2014 genetic study, the lineage may have split off from their closest relatives, a group of seabirds that today includes albatrosses and petrels, around 60 million years ago.
The limited fossil evidence, though, suggests a deeper past. Consider the oldest known penguin, Waimanu manneringi, which lived about 61 million years ago in New Zealand.
In 2017, paleontologists found another penguin nearby that was about as old. This animal was different enough from W. manneringi to suggest that the birds were already a diverse bunch. That hints at an earlier emergence, perhaps more than 66 million years ago, when T. rex was still stomping around.
The roots of the word penguin are also debated. But according to most dictionaries, it derives from “pen gwyn,” the Welsh term for “white head.”
The word originally described great auks — a large, black-and-white, flightless aquatic bird that once called the Northern Hemisphere home.
In the 16th century, The Golden Hind was exploring South America’s Strait of Magellan when a Welsh sailor aboard noticed a black-and-white aquatic bird. Thinking it resembled an auk, he called it a penguin.
Great auks went extinct in the mid-19th century, but their Welsh name lives on, forever associated with a completely unrelated bird. Now that’s auk-ward.
Auks were limited to the North Atlantic, while penguins are Southern Hemisphere-only animals — almost. The territory of the endangered Galapagos penguin straddles the equator.
You might think of Antarctica as Penguin Central, but it’s the exclusive home of only two species, the emperor and the Adélie. Most species don’t even hang out on ice.
The African penguin, as its name suggests, can be found on southern African coastlines. The Humboldt penguin, meanwhile, likes to build nests on high ground along the rocky beaches of Chile and Peru.
On New Zealand’s South Island, the yellow-eyed penguin, also known as the Hoiho, prefers forested or grassy locations. The least social of penguins, they space their nests well apart and hidden from each other.
The South Island’s mountainous, dramatic southwestern coast is home to breeding colonies of the Fiordland penguin, though the animals don’t maintain residence there year-round.
In August, a study published in PLOS ONE revealed that adult Fiordlands swim more than 1,500 miles from the colonies to specific feeding grounds in the Southern Ocean, covering sometimes more than 4,000 miles total, once the breeding season is over.
These epic journeys, called pre-molt dispersals, are crucial for survival. During breeding and chick-rearing on land, when foraging opportunities are restricted, Fiordlands, like other penguins, can lose 50 percent of their body mass.
After chick-rearing, the birds have about two to three months to head far out to sea — the pre-molt dispersal — and eat as much as they can to put weight back on before what’s called catastrophic molting.
That’s not as bad as it sounds: Unlike gradual molting, which most other birds experience, penguins’ old feathers are rapidly shed and replaced. That “catastrophic” speed is important because, during this weeks long transition, the birds’ coats are not waterproof and they must stay on land, going hungry.
Those feathers are uniquely adapted for swimming in chilly water. While there is some variation among species, penguin feathers have features such as tiny interlocking barbs to trap air, hinder heat loss and repel water.
In June, a study of feathers from nine penguin species found other unique microstructures, now associated with coloration, probably first evolved in the marine birds for improved hydrodynamics. The journal that published the paper? The Auk.