The only penguins found in the northern hemisphere are endemic Galapagos penguins (Spheniscus mendiculus). Unlike their arctic brethren, Galapagos penguins must adapt to heat since their population straddles the equator. Besides cooling themselves in the water, they hunch over to shade their feet and pant like dogs to cool their throats and nasal passages.
Galapagos penguin populations decline in El Nino years, when sea temperatures remain warm and food (small fish like sardines) becomes scarce. The penguins’ breeding cycle is driven by sea surface temperatures, and they often do not breed at all in El Nino years. In addition, invasive dogs, rats and cats eat the eggs and destroy their nests. Our guide told us that scientists worry that the current population could not survive another El Nino. With fewer than 1000 breeding pairs, the Galapagos penguin is the rarest penguin in the world.