Physical appearance[edit]
Rockhopper penguins are one of the smallest species of penguin in the world. They range from 2.3-2.7 kg where males are larger than females.[1] After reaching full growth, they are about 20 inches in height.[2] Males and females cannot be distinguished just by looks, so a DNA test is conducted by taking a feather from the bird to determine its gender.[1] Like many penguins, rockhopper penguins have a white belly and the rest of their body is black.[1] Some characteristics that differentiate them from the other penguins are their red eyes, orange beak, pink webbed feet, and the yellow and black spiky feathers they have on their head.[2][3] Although their yellow and black spiky feathers differentiate them from other penguins, rockhopper penguin chicks do not have them; these feathers develop with age.[3] Their orange beak is initially black, but as the penguins get older, their beaks turn orange.[3] Due to the harsh rocky environment, they cannot slide on their bellies like most penguins, so they hop to get from one place to another