Groups of emperor penguins protect from the cold due to social huddling.

Introduction

Emperor penguins breed during the cold Antarctic winter, where temperatures can reach -30C and below. To conserve energy and protect themselves from the cold, they adopt a behavioral strategy of huddling close together in large groups. Huddling is considered key to their ability to live in such a cold place. They have different huddling patterns across different breeding stages, with the largest number of penguins huddling during the egg incubation period, when the males must survive fasting while also trying to keep their eggs warm.

The Strategy

Within a huddle, emperor penguins shift their position in a wavelike movement. Every 30-60 seconds a penguin will move, triggering neighboring penguins to also move. These actions/reactions result in a wave of movements across the huddle, which over time leads to large scale movement of the huddle. This can increase the size of the huddle, by allowing smaller huddles to eventually join together. These small movements also affect the organization of the huddle by increasing the density, from creating a more orderly arrangement as each penguin finds their ideal position.

 

Penguin huddle
Image: Caroline Gilbert, Stéphane Blanc, Yvon Le Maho, André Ancel / CC BY SA ‑ Creative Commons Attribution + ShareAlike

Male emperor penguins huddle to stay warm while females spend months foraging for food.

Penguins exposed to the cold, harsh Antarctic winds rotate to the back, then inward towards the middle, and eventually back to the front again, which creates a constant wave‑like motion through the huddle.

Over time, huddles grow larger as individual penguins join or other huddles join together, causing the penguins to be more tightly packed together, which can sometimes cause the penguins to get too hot. When they need to get rid of the excess heat, the penguins leave the huddle in an abrupt breakup. This relatively slow increase in huddle size followed by rapid separation is a behavior that further allows them to regulate their exposure to unwanted temperature.

Lens of Time: Huddle Masters | bioGraphic

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Emperor penguins just may be the best huddlers on Earth—and scientists are finally revealing the secrets to their success.

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Last Updated August 20, 2018