Watch The Milwaukee Zoo Penguin Weigh-In

MILWAUKEE COUNTY, WI — The Milwaukee County Zoo has 16 Gentoo and Rockhopper penguins, and once a month zookeepers give their flippered friends a friendly weigh-in.

This video, shared by the zoo on Jan. 5, shows a keeper handing penguins a small fish called a capelin to encourage them to walk onto a square rubber pad that serves as a scale.

One by one, the penguins plod their webbed feet over a door threshold onto the pad. At times, they jump over the scale, or plop two at a time on the scale in the pursuit of a fishy treat.

Rockhopper penguins — the ones in the video with the crested head and yellow bands above the eyes — is considered one of the world's more numerous penguin populations, though estimates indicate that the population has decreased by nearly 90 percent since the start of the 20th century.

The Gentoo penguins are the larger of the two penguins shown in the video and are known for their white bonnet-shaped stripe across the top of their head. They're commonly found in Antarctica and nearby islands.

Image Via Milwaukee County Zoo