Galapagos penguin  The Galápagos penguin ("Spheniscus mendiculus") is a penguin endemic to the Galápagos Islands. It is the only penguin found north of the equator. The cool waters of the Humboldt and Cromwell Currents allow it to survive despite the tropical latitude. The Galápagos penguin is one of the banded penguins, the other species of which live mostly on the coasts of Africa and mainland South America. The average Galápagos penguin is long and in weight. It is the second smallest species of penguin, after the little penguin. Galápagos penguins have a black head with a white border running from behind the eye, around the black ear coverts and chin, to join on the throat. They have grey-black upperparts and whitish underparts, with two black bands across the breast, the lower band extending down the flanks to the thigh. Juveniles differ in having a wholly dark head, greyer on side and chin, and no breast band. Females are smaller than males. Ninety percent of Galápagos penguins live on Fernandina Island and the west coast of Isabela Island, in the western part of the archipelago, but small populations also occur on Santiago, Bartolomé, northern Santa Cruz, and Floreana. The northern tip of Isabela crosses the equator, meaning that some Galápagos penguins live in the northern hemisphere, the only penguins to do so. The penguins are confined to the archipelago, foraging in the cool Cromwell Current during the day and returning to the land at night. They eat small schooling fish, mainly mullet and sardines, and sometimes crustaceans. They normally range only a few kilometers from their breeding sites, depending on the cold, nutrient-rich currents to bring them food. Air temperatures in the Galápagos remain in the range . During El Niño seasons, the penguins defer breeding because their food becomes less abundant; this makes the chances of raising offspring successfully unfavorable compared to the chances of dying in the attempt. This was especially detrimental during the 1982-83 El Niño, where a decline in population of 77% was observed. The penguins usually breed when the sea surface temperature is below . The strong tropical sun is problematic for this species. Their primary means of cooling off is going in the water, but other behavioral adaptations for thermoregulation come into play when they must remain on land.