Penguin

Winter breeders

While most birds avoid the Antarctic winter, emperor penguins march inland to traditional breeding sites — sometimes 100 km from the sea — and lay a single egg in May or June, just as temperatures drop to −60 °C. The female passes the egg to the male and returns to the ocean to feed; the male incubates the egg on his feet, under a fold of belly skin, for about 65 days, fasting the entire time.

Huddling

Standing in the open at −40 °C with 200 km/h winds requires extraordinary thermoregulation. Males huddle tightly together, slowly rotating so that birds on the windward edge cycle into the warm interior of the huddle. Temperature inside a huddle can reach +37 °C; the system distributes heat — and warm-up turns — fairly across hundreds of birds.

Diving deep

Emperors are the deepest-diving birds in the world. They’ve been recorded at 565 m, well beyond the depth at which their lungs would collapse if they didn’t hold a sealed pocket of air. Dives can last over 20 minutes. Their hemoglobin and myoglobin store extra oxygen, and their hearts slow dramatically during a dive.

A future under threat

Emperor penguins depend entirely on stable sea ice for breeding, molting, and access to fishing waters. As Antarctic sea ice declines, several colonies have already failed to fledge any chicks in recent years. The species was uplisted to Near Threatened in 2012 and may move to Vulnerable as warming continues.