Emperor penguins are one of nature's great survivors. They can endure the frigid cold of an Antarctic winter, when temperatures plummet to -20 °C or below. To prevent themselves freezing to death, they huddle together in tightly-packed groups to conserve heat and shelter themselves from the intense winds.
Now it seems these huddles can actually be too good at keeping the emperor penguins warm.
In a video time-lapse available on BBC Earth, you can see that penguin huddles constantly rotate. The most obvious behaviour is that penguins on the outskirts regularly muscle their way inside the huddle.
That is easily understandable. Those on the outside of the huddle face the direct hit of Antarctica's icy wind chill.
But there is something else going on. The penguins on the inside get too hot, so after a while they need a little room to cool off.
Penguins seeking to lose some body heat actually break huddles apart, say researchers in a new paper in the journal Animal Behaviour. Within the huddles, penguins barely lose any heat. The little they lose comes from their heads, or from breathing in icy air.
Read the full article here.