Fat Penguin Week 2026
All week we’ve reviewed the candidates. One penguin stood out… mostly because it’s round. The winner of our first annual Fat Penguins Week is Tractor!!
Thank you to everyone who took part in our Fat Penguins Week. We hope you enjoy participating as much as we had fun preparing it 🐧 We’d also like to thank Anna Testorf, an undergraduate Biology major at UW, for coming up with this amazing idea and captured a lot of the media used during FPW 2026. If you had fun following along be sure to follow us on our various platforms and subscribing to our quarterly newsletter. There’s always something going on with the Center.
Scroll down to review all of the facts we posted about juveniles, molting, and preening.
Fat Penguin Week Intro
This year we are holding the first annual Fat Penguins Week! In late austral summer and early austral fall, Magellanic penguins undergo their annual catastrophic molt. For approximately 19 days, juvenile and adult penguins avoid the water and shed their old feathers (Borboroglu & Boersma, 2013). Once all of their feathers have been replaced by clean new ones, the penguins return to the ocean for their annual migration. They won’t be back to Punta Tombo until September!
Join us as we celebrate the fattest juvenile Magellanic penguins of Punta Tombo! Cast your vote between Feb 23-27 2026 using the link below, and check back on our socials for more facts about juvenile penguins and molting.
Help us crown the champion: vote for the best fat juvenile penguin. 🐧🗳️
Why do penguins bulk up before their molt? Penguins are forced to fast through the molting process. To prepare for the shedding of all of their feathers, penguins stop preening and oiling their feathers. The pause in feather maintenance renders their feathers water permeable – that’s not a good thing for a seabird! Since they can’t go into the ocean to forage, penguins have to fatten up in order to survive their molt.
Juvie Facts
Juvenile fact: What makes a juvenile Magellanic penguin a juvenile? A juvenile Magellanic penguin is one that has already fledged (started swimming), but has yet to obtain their adult plumage. How do they get their adult plumage? By molting, of course!
Juvenile fact: How can you tell a juvenile penguin from chicks or adults? Juveniles are around the same size as adults, but lack the distinctive black bands on the head, neck, and breast. Their feathers have a dull, grey color instead of stark black and white (Borboroglu & Boersma, 2013).
Molting Facts
Molting fact: Molting can actually begin in late January, with juveniles and young adults molting first. The molting season can last until April (Borboroglu & Boersma, 2013).
Molting fact: Magellanic penguins shed their head, neck, and flipper feathers last (Borboroglu & Boersma, 2013).
Feather Facts
Feather fact: What’s preening? Preening is a maintenance behavior done by all birds to care for their feathers. For Magellanic penguins, preening includes using their bills to rearrange feathers and to coat them in preening oil.
Preening fact: Why do penguins have to rearrange their feathers? The arrangement of feathers helps keep penguins warm and dry while diving in cold ocean waters. Penguins have to stay vigilant in preening to make sure their feathers are properly layered or cold water might permeate their outer feather layers.
Molt Prep Facts
How do penguins prep for the molt? Magellanic penguins go on a pre-molt foraging trip, where they eat as many fish as they can. Right now, as juvenile and young adult penguins molt, adult penguins are on their pre-molt trip. Our field crew attached satellite tags on 19 adult penguins; track them right now on our live penguin tracking page!