Scientists have discovered that Emperor penguins face new risks during their annual feather moult as Antarctica warms.
Each year, the birds remain on floating ice platforms to replace old, weather-beaten feathers with new, waterproof coats. This process is critical for survival, but it also leaves them vulnerable.
Between 2022 and 2024, Antarctic sea ice shrank drastically due to climate change. The loss of stable ice platforms deprived penguins of safe places to complete their moult. Now, satellite tracking shows that many birds have disappeared. Researchers fear that thousands may have frozen in the icy waters.
Dr Peter Fretwell of the British Antarctic Survey, who has studied Emperor penguins for 20 years, called the findings “game-changing.” He said, “This was really an ‘oh my God’ moment. Suddenly you’re thinking, well, have we got time to save them?”
The research, published in the journal Communications Earth & Environment, highlights the impact of the collapse of Antarctic summer sea ice in West Antarctica. The region is home to 30-40% of the global Emperor penguin population, one of the most threatened in the world.
During the catastrophic moult, penguins travel thousands of kilometres to find stable ice and spend 30-40 days replacing their feathers. Satellite images from 2019 to 2025 revealed large brown smudges in Marie Byrd Land, which turned out to be piles of discarded feathers.
Emperor penguins’ feathers are highly specialized. They provide the best insulation of any animal, but they wear out over time. Annual shedding is essential, though it uses up to 50% of the birds’ body mass.
Fretwell emphasizes that the energy-intensive process combined with shrinking ice makes the penguins increasingly vulnerable in a warming Antarctic world.
