A Pint-sized Penguin’s Pacific Partnership

Written by Simon Mustoe



Galapagos Penguins live on the equator. They never see icebergs and being flightless, make a living confined to a small area.

Venturing out to sea isn’t an option for this pint-sized penguin. It risks predation by sharks and saps valuable energy - both high risk strategies for a small bird in a cold ocean. 

To survive all the world’s penguins need an abundant and reliable food source within swimming-distance of their nest. In Australia, Little Penguins deliver food daily to newborn chicks, while one parent remains at home to keep the fledgling warm. With a maximum swim-speed of about 3kph their effective shopping radius is only 10-20km.

Galapagos Penguins are even more range-constrained. 

There’s a further twist in the story. It’s in an unlikely union with one of the Pacific’s biggest oceanographic features, the Pacific Equatorial Undercurrent (PEU). 

The scale of this ocean feature is vast. It’s 3,500 miles long and 250 miles wide. Yet it’s only provided marginal opportunity for the evolution of this unorthodox tropical seabird. 

The current strengthens and weakens over time. During El Niño, when the Pacific Ocean warms and trade-winds effectively reverse, the current almost stops and Galapagos Penguin populations crash through lack of food. You could say the relationship is a bit one-sided but it is nevertheless a fascinating example of how sensitively evolution's balanced. 

To understand the significance of any species on Earth, you need to visualise the context of its existence related to the physical, chemical and biological world. 

Let’s start with the basis for global ocean movement, the humble water molecule.

These magnetic dynamos, comprising a negative oxygen atom at one end and two positive hydrogen atoms at the other, bind together at Earth’s cool temperatures to create a liquid with just the right viscosity and properties to influence evolution at every conceivable spatial scale. In this case, its an effect that moves a whole ocean and occupies half of planet Earth. It is almost almost singularly responsible for the existence of Galapagos Penguin.  

To understand how the current works, imagine the Pacific Ocean as a steep-sided mixing bowl.

Drop some glitter in the bottom and with a wooden spoon, repeatedly sweep the surface from right to left. The glitter should move in the opposite direction, from left to right, because the all water molecules are coupled. With continuous sweeps, you’d set up something akin to a conveyor belt. Viewed from the side, the water flows around and around, a circular motion, so the surface goes in the opposite direction to the bottom.     

This is exactly what happens in the PEU but the ‘belt’ is a few hundred metres below the surface and moves a mass of 30 million cubic metres a second, steadily eastwards. The trade-winds that blow surface water east to west, are the ‘wooden spoon’ and are created by the rotation of the Earth. It’s these trade winds that reverse during El Niño years, effectively halting the PEU.  

When the undersea current collides with the Galapagos Islands’ western volcanic slopes, much like the side of the mixing bowl, nutrients (the glitter) rise to the surface.

In the deep waters of the mid-Pacific, there is a gargantuan biomass of foraging squid and fish, a voracious food chain that generates huge quantities of decay and nutrients that, were it not for these massive currents, would settle into the abyss. When they are swept into tropical coastal waters, which are traditionally resource poor, it nourishes the ecosystem. Ultimately the penguins’ favourite prey flourish and the penguins can enjoy a productive breeding season. 

Limited to only a couple of kilometres offshore and needing waddle-able beach-access to colonies, the penguins are distributed along the less precipitous coasts of northern and eastern Fernandina and in the Elizabeth Bay area of Isabela. These western islands are closest to the current’s nutrient upwelling action. 

So Galapagos Penguins have become a barometer for a planet-scale process, which is testament to the long-term stability of the Pacific ocean and its weather systems. These systems have created the unique conditions on which the Galapagos Island’s wildlife evolved over millions of years. 

However, uncertainty about the strength of the current has meant that Galapagos Penguins have had to adopt more extreme survival strategies than their southern ocean counterparts. 

First, there is a higher risk of predation from sharks and other predators in tropical upwelling zones.

In the Antarctic, food is distributed more broadly (so predators are less concentrated), penguins forage in bigger groups and individual risk is diluted. Galapagos Penguins respond to this risk by foraging in groups when venturing further offshore but are also commonly seen in ones or twos in the shallows.

The video above (by Chris Seers) was taken from a snorkel just beyond the volcanic slopes. 

All other penguins have a specific breeding season, while Galapagos Penguins reproduce whenever conditions are favourable.

Some years they may breed twice, other years not at all. Spreading out across different colonies means populations can ‘hedge’ survival risk and while there are winners and losers, any population will be sustainable in the long-term if it stays roughly at the right capacity for the local environment. 

Being ready to breed at any time is a costly strategy but one that has served to maintain Galapagos Penguin populations, even despite the occasional crash, due to the PEU’s inaction.

One of the more energy-intensive tasks for any penguin is to moult.

Moulting is really energy-intensive because it means replacing all feathers in one go and this can only be done while fasting on land for at least two weeks. Galapagos Penguins lead a life of double jeopardy. Daytime air temperatures on the colony soar to 40ºC while water temperatures are as low as 20ºC. The internal temperature of a moulting bird in seawater can drop by six degrees in just 30 seconds. So moulting is critical to maintain insulation - it's literally the bird's survival suit.    

One of the wonderful and poetic things about ecology is when you begin to understand the sheer sensitivity of systems to change and the narrow margin-for-survival that most species endure. 

It’s almost unimaginable how Galapagos Penguins have persisted for almost two million years. 

Up until recently, the climate (which as we’ve discovered is inextricably linked to ocean processes) has been relatively stable - at least over short-enough time scales to allow adaptations to occur. Penguin populations have even survived ice-ages.      

Evolution thrives when fluctuations in ecosystem processes in the short term are just enough to create opportunities but stable enough in the long-term to give things chance to adapt.  A complex but predictable ecosystem creates what ecologists call ‘niches’. Economists might refer to them as gaps in a market. In many ways, ecology is uncannily similar to the way our own society works. 

For example, the appearance of a town’s first local printer could be be pivotal in setting up a local newspaper and enabling a range of businesses to create posters, print letters and generate trade with other towns and between businesses. 

You only need to see a coral reef to observe the way that a bewildering number of animals eek out their own unique territory in time and space but couldn’t exist if it wasn’t for the coral bodies and other animals interdependence on each other. 

But once a species has a foothold and a strategy in place, it’s hard to displace, unless something big comes along and upsets the status quo. if you tried to set up a printing company in a small town where several already existed, you might struggle.  

Volcanic eruptions some 4.2 million years ago created the Galapagos Islands and a whole new set of conditions for the rapid evolution of species, including Galapagos Penguins, which appeared about 2 million years ago.

If you’ve ever wondered, this is why the Galapagos is considered the laboratory for evolutionary biologists and explains how it had such a profound influence on scientists such as Charles Darwin.  

So we learn that maintaining diversity is important for ecological integrity. Likewise, we take our economic ecosystem so seriously, we put stringent laws in place to ensure trade flourishes. We combat monopolies and make restrictive trade illegal. Unless we protect the systems, the economics break down.

It’s not hard to imagine the impact that ecosystem breakdown could have on our own society as we are each living through the changes right now and watching them unfold as natural disasters every day on our news screens.  

So the appearance of Galapagos Penguins was premised on a geological twist of fate, when a crack in the ocean crust appeared and lava was thrown up to first create these islands, 1,000km off the coast of Ecuador.

Descended from cousins who still live today on the western shores of South America, these avian cast aways carved out a new ‘niche’ in the only way possible - through hundreds of thousands of years of unintentional trial and error. 

What you see today, is the result of a process that has created all life on Earth as we know it.  A species perfectly suited to its natural environment and a notable component of a treasured natural asset. Its existence is like the emphatic highlights on an impressionist painting. Too many brush-strokes and the image becomes unvaried and unappealing. Just, just the right amount and it brings the canvas to life, accentuating the story and details beneath. 

The Pacific Equatorial Undercurrent, a planet-scale process that creates the condition for it to exist, is beamed squarely onto the Galapagos island food web. This story elegantly focuses us on something about the meaning of life on earth.  

What studying species such as Galapagos Penguin teaches us is that ecosystems are very finely poised. Their integrity arises from influences at a bewildering array of scales from molecular to planet-wide, patiently evolving over millennia.  

Ecology is an extraordinary thing. You can take an example of almost any species on Earth, from the Galapagos Penguin to the animals and birds that live around the creeks and waterways in your local park, and build a similarly convincing story. After all, we all came from the same place and ultimately, as humans, we share the same planet and we live among and depend on the same things for our survival. 

Wildiaries •