At first, penguins with chicks circulate on the outside,
avoiding the pressure within.
As the weather worsens, they'll all have to look for a place to tuck in.
Eventually, a huge huddle forms.
While those in the centre are warm and protected,
those on the outside are still struggling.
To share the heat around, the penguins take tiny steps to change position.
Waves of movement ripple through the huddle,
giving everyone a chance to have a go in the centre.
The huddle is so efficient, penguins in the inner core can even overheat.
As these penguins try to cool down, the colony starts to break up.
The collapse acts as a release valve, shedding excess heat.
But it's dangerous for the chick.
As everyone moves position, some mothers topple in the crush.
She tries to stop her full weight falling on her chick.
Getting back up is especially difficult, with a chick nestled in her pouch.
Her care finally pays off.
She and her chick rejoin the huddle, as it starts to reform.
Not all have been so lucky.
This penguin has been searching for her lost chick.
She hopes it might still be alive.
Her pouch is the only lifesaver she knows.
A female companion shows her concern.
The mother invested everything into her chick.
To lose it is a tragedy.
She will have to wait another year.