Penguins, People, and Climate Change
How penguins adapt to Antarctic warming tells us much about ourselves.
Posted Jan 16, 2020
Some penguin populations are crumbling in the face of Antarctic warming. Others are changing their behavior and prospering, telling us a great deal about human adaptability.
The Bad News First
Researchers are looking at the impact of climate change on three species of penguins in the Antarctic Peninsula. This is a neck of land to the northwest of the continent that stretches towards Patagonia.
The Antarctic Peninsula is currently ground zero for climate change and two species have suffered huge population declines. Chinstraps are down 50 percent and adelies (that are identified by white circles around the eyes) are down 75 percent. Astoundingly, the population of gentoo penguins in the region increased by a factor of six.
The declining populations were hit by a double whammy. Their diet is mainly krill—small crustaceans. These animals are under assault both by global warming that reduces nutrients in the water and by commercial exploitation of krill for the dietary supplement industry.
Warmer conditions have brought more water vapor in the atmosphere and an increased amount of snow. This is bad news for penguins that typically breed on bare rocks. Snow causes many of the nests to fail.
The problem for the adelies and chinstraps is that they were unable to adapt to changing conditions. The gentoo population provides a remarkable example of evolutionary resilience in the face of altered conditions.
Gentoo Penguin Behavioral Adaptations to Climate
Gentoo penguins are identified by white patches across the head and red bills. Their challenges from climate change are essentially the same as the other two species—declining krill populations and difficulty breeding on the snow-covered ground.
Yet, the gentoo population is thriving. How do they do it? They responded to declining krill by shifting to eating larger fish prey. When the nest failed, gentoo penguins began breeding again so that the breeding season was not wasted.
This is a remarkable story of behavioral adaptation that occurred within the lifetime of an individual. Species that are incapable of this sort of behavioral flexibility are extremely vulnerable to climate change and are currently being taken out by natural selection in the Antarctic Peninsula even as the gentoo thrive.
Here we find a compelling example of adaptive change occurring for an entire species over a very short time frame.
This conflicts with conventional gene-selection accounts of evolution where gradual change occurs on a time scale of millions of years.
This phenomenon is of great relevance to human evolutionary history because our species is second to none when it comes to succeeding under varied ecological conditions.
The Human Evolutionary Trajectory
The fact that some species adapt much better to climate change than others is of great intrinsic interest for environmentalists. There are winners as well as losers.
Unfortunately, we do not understand the underlying mechanism of gentoo adaptability. Are they generally more flexible in their behavior? Do they have more variability in their response to day length, which is the main stimulus for seasonal breeding? Are their dive depth and feeding behavior inherently more varied.
All we know is that natural selection favors the gentoo form of feeding and reproductive behavior and that it does so with startling rapidity.
Such rapid evolutionary change is familiar from our own species that quickly moved from hunting and gathering to sedentary agricultural production after prey animals disappeared due to overhunting. Of course, our foraging practices took an even more dramatic change with the Industrial Revolution and reliance upon a trading economy as the primary source of food.
Long before the advent of agriculture, our ancestors left their primeval forests that still sustain other primates and wandered restlessly throughout the globe. Evidently they were so successful as hunters that they depleted local game sources and moved on in search of new opportunities.
Whether it is humans or gentoo penguins, some species are more successful at adapting to ecological change than others are. This is the likely reason that humans overspread the globe. We became so reproductively successful that we are depleting planetary resources and bringing about the climate changes that threaten penguins.
Implications for the Social Sciences
All of this is of clear relevance to endangered species but why should psychologists pay particular attention?
Like the gentoo, human behavior is exquisitely sensitive to varied ecological conditions. This is why our species could occupy so many different habitats and achieve Darwinian success unrivaled by any other primate.
We are responding to information-rich modern conditions with an increased capacity to process much complex information quickly, for instance (the Flynn Effect, 1). At the same time, close reading modified the shape of the developing eyeball, resulting in a great deal of shortsightedness that is unknown in ancestral societies.
While our population is currently in the middle of a population explosion, like the gentoo on the Antarctic Peninsula, family size is declining in developed countries partly due to the increased expense of raising children.
This may be a bigger threat to our population even than climate change.
In evolution, past success is no guarantee of future success.
1. Barber, N. (2020). Evolution in the here and now: How adaptation and social learning explain humanity. Amherst, NY: Prometheus/Rowman and Littlefield. https://rowman.com/ISBN/9781633886186/Evolution-in-The-Here-and-Now-How-Adaptation-and-Social-Learning-Explain-Humanity
https://www.pbs.org/video/leading-edge-warnings-from-antartica-1554336712/ Ron Naveen penguin counter, etc.