Juveniles are colored black on the back and medium grey on the chest. Humboldt penguins usually breed in September and February. Incubation is provided by both sexes and lasts five weeks. Usually two eggs are laid, although three or four are not unknown. The young leave the nest about one month after hatching.
Nests are guano burrows.
They live in large colonies called rookeries. Most swim at 15 mph which is the speed the fastest human can run, or about four times the speed of a human swimmer. On land they stand erect and waddle from place to place. Like all penguins, Humboldt penguins are flightless. There were 51 known species, but only 18 remain today.