Scientists Analyzed Penguin DNA And Found Something Quite Remarkable

Penguins are no strangers to climate change. Their life history has been shaped by rising and falling temperatures, and their bodies are highly specialized for some of Earth’s most extreme conditions.

And yet, scientists are concerned the evolutionary path of the penguin may be grinding to a halt, thanks to what appears to be the lowest evolutionary rates ever detected in birds.

A team of international researchers has just published one of the most comprehensive studies of penguin evolution to date, which is the first to integrate data from living and fossil penguin species.

The research unveils the tumultuous life history of penguins in general, with three-quarters of all known penguin species – now represented by fossils only – already extinct.

“Over 60 million years, these iconic birds have evolved to become highly specialized marine predators, and are now well adapted to some of the most extreme environments on Earth,” the authors write.

“Yet, as their evolutionary history reveals, they now stand as sentinels highlighting the vulnerability of cold-adapted fauna in a rapidly warming world.”

On land, penguins can appear a bit ridiculous, with their awkward waddle and seemingly useless wings. But underwater, their bodies are transformed into hydrodynamic torpedoes that would make any fleeing fish wish it could fly.

Penguins had already lost their ability to fly 60 million years ago, before the formation of the polar ice sheets, in favor of wing-propelled diving.

The fossils and genomic data suggest the unique features that enable penguins’ aquatic lifestyles emerged early in their existence as a group, with rates of evolutionary change generally trending downwards over time.

The scientists think penguins originated on a Gondwanan micro-continent called Zealandia, which is now mostly submerged under the ocean.

The paper suggests the ancestors of modern penguins – crown penguins – emerged approximately 14 million years ago, a whole 10 million years after genetic analyses have hinted at.

This particular period would coincide with a moment of global cooling named the middle Miocene climate transition. Living penguins, however, split into separate genetic groups within the last 3 million years.

Penguins spread out across Zealandia before dispersing to South America and Antarctica multiple times, with later groups likely hitching a ride on the Antarctic Circumpolar Current.

The scientists found that almost every penguin species experienced a period of physical isolation during the Last Glacial Period.

Their contact with other penguins was limited during this time, as groups were forced to live in more fragmented areas of habitat further north, where they could still find food and shelter.

As a result, the DNA pool of each group became narrower, pushing species further apart genetically.

In the period of warming that followed, they moved back towards the poles, and some groups, now much more genetically distinct, crossed paths once more.

The way certain groups of penguins experienced these significant climate events offers insight into how they might cope with human-caused climate change.

The groups that increased in number when warming occurred…