The Galapagos Penguin (Spheniscus mendiculus) is a penguin endemic to the Galapagos Islands. It is the only penguin to live on the equator. Its nearest relatives are the African Penguin, the Magellanic Penguin and the Humboldt Penguin. 

Galapagos Penguins grow to 53 cm tall. They 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 blackish-grey upperparts and whitish under parts, 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. 

The Galapagos Penguin mates for life. It lays one or two eggs in places such as caves and crevices, where darkness will prevent the eggs to overheat. One parent will always stay with the eggs or chicks while the other is absent for several days to feed. If there is not enough food available, the nest may be abandoned. 

The species is endangered, with an estimated population size of 600 pairs only. The population underwent an alarming decline of 65% since the mid-1990s which makes it the rarest penguin species (a status which is often falsely attributed to the Yellow-eyed penguin). In recent decades the effects of the El Niño Southern Oscillation on the availability of shoaling fish have influenced this species but anthropogenic factors (e.g. oil pollution, fishing by-catch and competition) also add to the ongoing demise of this species. On Isabela Island, the introduced cats, dogs and rats may attack penguins and destroy their nests.