Climate change is something that penguins are familiar with. Their life history has been shaped by rising and falling temperatures, and their bodies are very specialized for extreme conditions.
The evolutionary path of the penguin may be grinding to a halt due to the lowest evolutionary rates ever detected in birds.
One of the most comprehensive studies of penguin evolution to date has just been published by a team of international researchers.
Three-quarters of all known penguin species are already extinct thanks to the research.
The authors write that the birds have evolved to become highly specialized marine predators and are now well adapted to some of the most extreme environments on Earth.
As their evolutionary history shows, they now stand as protectors of cold-adapted fauna in a rapidly warming world.
On land, penguins can look a bit silly, with their waddle and wings. Their bodies are turned into torpedoes that would make fish want to flee.
Before the formation of the polar ice sheets, penguins had lost their ability to fly.
The fossils and data show that the unique features that enable penguins' aquatic lifestyles emerged early in their existence as a group.
Zealandia is a Gondwanan micro-continent that penguins are thought to have originated on.
According to the paper, the ancestors of modern penguins emerged approximately 14 million years ago, a whole 10 million years after genetic analyses have indicated.
This particular period would coincide with a cooling of the world's temperature. Within the last 3 million years, penguins split into different groups.
The penguins spread out across Zealandia before moving to South America and theAntarctica.
The penguins experienced a period of physical isolation during the Last Glacial Period.
During this time, groups of penguins were forced to live in more fragmented areas of habitat further north, where they could still find food and shelter.
As a result, each group's genetic pool became smaller.
After warming, they moved back towards the poles, and some groups crossed paths again.
The way certain groups of penguins experienced the climate events offers insight into how they might deal with climate change.
The groups that increased in number were migratory. The ability to look further away for prey and to move to lower latitudes were some of the features that allowed them to respond better to changing climates.
A lifestyle that doesn't cope well when the conditions at home change is what those that decreased in number did.
penguins' ability to change may be limited by more than just lifestyle
penguins have the lowest evolutionary rates of any bird species, along with their sister order, Procellariiformes.
Several genetic signatures were used to compare 17 different orders of birds.
They noticed that aquatic birds had slower rates of evolution than theirTerrestrial kin, so they think the adoption of an aquatic lifestyle might go hand in hand with low evolutionary rates. Evolutionary rates in birds are lower in cooler climates, according to them.
The order Galliformes, which includes seafaring birds like pelicans and cormorants, was a third of the way to the lowest evolutionary rate.
Even though crown penguins evolved at a faster rate than living penguins, this was still slower than other birds.
Half of all penguin species are at risk of dying out, and the scientists say their slow evolutionary rates and niche lifestyles could cause them to do so.
The current pace of warming combined with limited refugia in the Southern Ocean will likely far exceed the ability of penguins.
As penguin populations across the Southern Hemisphere are facing rapid climate change, the risks of future collapses are always present.
The research was published in a journal.
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