The Humboldt penguin (also known as the Chilean penguin, Peruvian penguin, or patranca) is a South American penguin that breeds in coastal Chile and Peru. The penguin is named after the cold water current it swims in, which is itself named after Alexander von Humboldt, an explorer. Humboldt penguins are visibly thinner than other species that store more fat and plumage in their body. The climate they inhabit is warm in some areas, and intense sunlight increases their body temperature. Considered medium-sized penguins, they grow to a length of 22–28 in and a weight of 8-13 lbs. They have a black head with a white border that runs from behind the eye, around the black ear-coverts and chin, and joins at the throat. They have blackish-grey upperparts and whitish underparts, with a black breast-band that extends down the flanks to the thigh. They have a fleshy-pink base to the bill. Juveniles have dark heads and no breast-band.
Raised in rocky habitats, they are also excellent climbers able to perform jumps with both legs and balance themselves with the help of their flippers. They cohabit easily with larger birds, such as pelicans. The penguins' torpedo-shaped bodies are designed for moving efficiently through water, and Humboldts can reach speeds of 30 miles per hour. They use their wings to help them swim, and their webbed feet to steer underwater. Their bones tend to be denser than those of flying birds, since the extra weight helps them dive to greater depths. Their vocalizations vary according to the circumstance; either to show aggression, recognize family members, engage in courtship, or coordinate as a group. Both partners emit a sound very similar to donkeys braying. Overall, they are very social penguins with largely peaceful behavior. One of the greatest dangers the Humboldt penguins face is becoming entangled in commercial fishing nets, as well as being the victims of illegal trade either for consumption or as exotic pets. The loss of their habitat, mining, human disturbance, and predation by introduced animals such as rats, cats, and foxes, also present significant threats.