Aside from the Arctic, the Western Antarctic Peninsula has warmed faster than anywhere else on the planet over the past six decades—some 5 degrees Fahrenheit on average year-round and a whopping 9 degrees F in the austral winter. That's not bad news for every species, though. In Antarctica, Gentoo penguins are widely considered a climate change winner, as they are more adaptable and can change their food stock of choice and expand their range as the ice melts. But ice floe–reliant Adélie penguins, in contrast, have declined on the Western Antarctic Peninsula.
Ultimately, this tale-of-two-penguins paradigm can tell us a lot about which types of species will be most successful amid climate change, according to Heather J. Lynch, an ecology and evolution professor and penguin researcher at Stony Brook University. Species that have a propensity to make adjustments in their habitat and food intake, she says, such as the Gentoo, can better withstand the challenges climate change presents.
By extension, researchers are using this behavioral divergence as a parable for how human beings can be more successful as climate change wreaks havoc on coastal regions with hurricanes and floods. Lynch says that stubborn human beings with an attitude that reduces to "By golly, we've lived on this sandbar for a hundred years and no stinkin' sea level is going to get us moving" tend to have more in common with the Adélie than the Gentoo.
Gentoos Can Take the Heat
Gentoos, with baby-carrot-orange beaks and white patches around their eyes, have the fewest numbers of any sub-Antarctic penguin species. They have a worldwide breeding population of about 387,000 pairs and exist mainly on the Antarctic Peninsula, the Falkland Islands and South Georgia. But from 1982 to 2017 amid rising temperatures, the number of Gentoo breeding pairs on the Western Antarctic Peninsula jumped from 25,000 to 173,000. Because Gentoos have adapted to be better suited to survive and reproduce than Adélies amid the changes the Western Antarctic Peninsula is seeing—warming water, less sea ice—they're in an advantageous position to expand their range as the habitat conditions shift.
The Adélie population numbers more than 4 million worldwide, but on the South Shetland Islands and along the Western Antarctica Peninsula, which have experienced the most dramatic warming, the number of Adélie breeding pairs plummeted from 105,000 to 30,000 from 1982 to 2017, a drop of more than 70 percent. Some Adélie colonies have seen their numbers free-fall by as much as 90 percent on the Western Antarctic Peninsula.
"Gentoo penguins have been successful, because they're highly adaptable, highly plastic," Lynch says. That manifests mainly in their go-with-the-flow approach to feeding and breeding.
In terms of securing food, Gentoos can swim up to 22 miles per hour and dive deeper to find food more quickly off the Antarctic Peninsula than Adélies, whereas Adélies rely on floating sea ice for feeding purposes, explains Dean Anderson, a research ecologist at Manaaki Whenua–Landcare Research in New Zealand.
That's because the sea ice that surrounds the Antarctic Peninsula in the winter acts as a substrate on which algae and microbes can grow; krill congregate around sea ice to feed on these species, attracting breeding colonies of Adélies that feed on the krill. But as temperatures warm and the ice pack is less plentiful, the Adélies can encounter feeding and lifestyle difficulties because they rely on krill for much of their diet.
"Penguins are pretty hardwired creatures—they don't have a lot of learned behavior," says Ron Naveen, president and founder of Oceanites, a nonprofit that has tracked penguin populations and climate change effects in Antarctica for the past 25 years. "The switch hasn't flipped yet. You can yell at [the Adélies] and say, 'please eat more fish, please eat more fish,' but they haven't quite gotten the memo."
Eventually and reluctantly, Adélies do switch over to fish in their diet and abandon their hungry chicks for days at a time to go in search of food. Gentoos, in contrast, transfer from krill to fish more readily and also don't need to make those long feeding runs.
The sea ice is also vital to the Adélies, because it can serve as "haul-out resting locations" for them during their days-long foraging trips that can total 30 miles, Anderson says. "They are awesome swimmers, but even they need a breather," he says. And the sea ice can also serve as a "free transportation service," he says, as the Adélies can move to and from foraging areas while resting in the pack ice. The sea ice also circulates at larger spatial scale across the Ross Sea and can help move the Adélies to the sea's northern edge in winter time when they use the extra hours of daylight to forage for food.
The Gentoos are more flexible when it comes to breeding, as well. Their willingness to look around for new habitat to breed in is a more forgiving strategy. The Adélies that return from the sea ice to the Antarctic Peninsula to breed appear less able to move to new locations as conditions change, because their suitable habitats are so few and far between, Lynch says, "that it has been beneficial over long periods of time to maintain fairly strict site fidelity."
"But the Gentoo are kind of like, 'Whatev,'" Lynch says. As conditions alter with warming temperatures, that unfazed approach is invaluable.
"Gentoo penguins, to anthropomorphize, are much more laid back," says Michelle LaRue, a lecturer at Gateway Antarctica, a center for Antarctic studies at the University of Canterbury in New Zealand, and a research associate in the University of Minnesota's Department of Earth Sciences. "For example, if they lose a clutch of eggs early enough in the season, they can actually lay more eggs." Adélies, on the other hand, do not.
Lessons for Human Beings
"There are real lessons there for humans, particularly in the context of hurricanes we've had recently and other flooding events," Lynch says. "At some level we have to decide if we're going to be like the Adélie or we're going to be like the Gentoo."
Lynch likens this behavioral divergence to the parable in Aesop's Fables of the willow and the oak, in which the former is willing to spread out and grow in other areas whereas the latter wants to stay firmly rooted in place.
"Are we going to be like the willow and kind of accept reality and look for the opportunities that we have and kind of call it quits where we have to?" Lynch says. "Maybe there are some portions of the coastline that are not suitable for habitation a hundred years out."
Sometimes obstinate human perseverance is not the optimal approach, just as the Adélies' stubborn commitment to what is inveterate can be detrimental to increasing their populations. Framing "we will rebuild" as a signal of strength, Lynch says, may not be an advantageous ideal.
The Gentoos do not resemble that type of intransigent resident. Sometimes a cut-your-losses-and-move-on strategy works better. Embracing change, and rolling with the punches, can offer the boost of flexibility.
In fact in 1909, about 65 degrees 10 minutes south of Peterman Island, where Naveen from Oceanites recently monitored penguins this season, famed French explorer Jean-Baptist Charcot spent time at what was the southern terminus of the Gentoo range on the Antarctic Peninsula. Now, the Gentoo have moved 20 to 30 miles more to the south.
Mobility and a willingness to reject rigidity in location can help human beings too. "I'm not sure that being the oak is the only sign of strength," Lynch says. "We have the capacity to be a bit smarter about it."
Nicolas Dubreuil, director of expedition cruises for the tour company Ponant, says passengers are increasingly learning important lessons of how to respond when confronting the realities of climate change.
"People living in the city, like most of our passengers, are completely disconnected from real nature in their every day," he says. "By observing first hand and being so close to penguins in their natural and difficult environment in Antarctica, passengers will be deeply touched and often realize that we cannot control Nature—that we have to adapt ourselves to survive."
"These penguins are a really good metaphor to consider what might happen to us humans if this type of warming comes our way," Naveen says. "When I go to the Antarctic, I think it's like a window on the whole world to see in front of you: whose numbers are changing; whose lives are as interesting as all get-out; and yes, you do—I do—think about how what they're going through may be replicated by us down the line."
"Penguins on the ice shelf or penguins on the edge of the Antarctic peninsula, they are canaries in the coal mine," Naveen added.
That climate change, a net negative for most species, is actually positive for the Gentoo complicates our approach to these shifts. Though the proper authorities and agencies will take measures to monitor and reduce our carbon footprint, the Gentoo offers a prescriptive solution for what to do as warming continues.
"Penguins are us," Naveen says. "Penguins have the same requirements of life as we do. If we can understand better what's going on in their lives, it might help us better understand what's going on with ours."
"It does give one pause that maybe the Gentoos are figuring it out for now, but once the Voigt Glacier melts away south of the Peninsula, or more of the Larsen C ice shelf breaks off, ultimately landscapes, icescapes, seashores are going to change," Naveen added. "And it could be the sea-level rise in the Antarctic is such that penguins are going to have to move up in elevation, just like the people in Miami are going to have to move to Georgia."