A new study from the University of California, Berkley has found that contrary to widespread beliefs, penguins evolved in Australia and New Zealand rather than Antarctica.
As part of a collaborative effort between museums and universities from across the globe, the researchers studied and analyzed 18 different penguin species. Using the genomic information obtained from blood and tissue samples, the scientists were able to trace the movement and diversification of the penguins throughout a period of over a thousand years.
And the findings of this study may rewrite everything scientists know about the origin of these flightless birds.
“Our results indicate that the penguin crown-group originated during the Miocene (geological period) in New Zealand and Australia, not in Antarctica as previously thought,” according to the study, published on Monday in the Proceedings of the National Academy of Sciences, CNN reported. “Penguins first occupied temperate environments and then [relocated] to cold Antarctic waters.”
The researchers posit that penguins likely first originated 22 million years ago, living in what is now Australia and New Zealand. However, some of them, ancestors of the emperor penguins and king penguins, eventually relocated to Antarctica, most likely due to an abundant food supply.
Eventually, around 10 million years later, the penguins were soon able to spread throughout the region. This is due to the body of water between Antarctica and South America – now known as the Drake Passage – fully opening up. As a result, penguins soon began to inhabit Antarctica, parts of Africa, parts of South America, some islands in the Indian Ocean and other subtropical regions. Indeed, some can even still be found in Australia and New Zealand, specifically the yellow-eyed, little and other crested penguins.
Not only does this research rewrite the understood origin of penguins, it also sheds new light on the ability of these flightless birds to adapt to new climates.
The study was able to pinpoint specific genetic adaptations the penguins used to thrive in new environments. This includes changes in genes used to regulate body heat, allowing them to survive in both subzero and tropical temperatures, an ability to dive deeper in the sea and osmoregulation – the process enabling them to survive on salt water without fresh water.
In addition, the study also seems to resolve a longstanding debate regarding the emperor and king penguins, which has long been hypothesized to be a sister group to all other penguins, due to being the only two species in the Aptenodytes genus.
“It was very satisfying to be able to resolve the phylogeny, which has been debated for a long time,” Rauri Bowie, professor of integrative biology at the University of California, Berkeley, and curator in the Museum of Vertebrate Zoology (MVZ) at Berkeley, said in a statement.
“The debate hinged on where, exactly, the emperor and king penguins were placed in the family tree, whether they are nested inside the tree closer to other lineages of penguins or whether they are sisters to all the other penguins, which is what our phylogeny showed and some other previous studies had suggested. And it fits with the rich fossil history of penguins.”
However, the study has also shed light on the challenges penguins face today due to climate change.
“We are able to show how penguins have been able to diversify to occupy the incredibly different thermal environments they live in today, going from 9 degrees Celsius (48 F) in the waters around Australia and New Zealand, down to negative temperatures in Antarctica and up to 26 degrees (79 F) in the Galápagos Islands,” Bowie explained. “But we want to make the point that it has taken millions of years for penguins to be able to occupy such diverse habitats, and at the rate that oceans are warming, penguins are not going to be able to adapt fast enough to keep up with changing climate.”
“We saw, over millions of years, that the diversification of penguins decreased with increasing temperature, but that was over a longtime scale,” explained Juliana Vianna, associate professor of ecosystems and environment at the Pontifical Catholic University of Chile in Santiago.
“Right now, changes in the climate and environment are going too fast for some species to respond to the climate change.”
Bowie and Vianna hope to build on this research, and plan to dive into the genetic variations found throughout the disparate populations of penguins.
“Penguins are very charismatic, certainly,” Vianna concluded. “But I hope these studies also lead to better conservation.”