Slide 1
Overlapping feathers help keep a penguin warm and dry
Penguin feathers help protect the bird from cold and wet conditions. Dense overlapping plumage forms an important part of its insulation.
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Fat beneath the skin provides another insulating layer and an energy reserve. Keeping warm is a combined body system, so feathers do not carry the entire task alone.
Slide 2
Preening keeps the protective coat in order
Penguins maintain their feathers through preening. An intact, well-arranged coat helps resist water penetration during swimming and diving.
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Oil from a gland contributes to feather care, but the physical arrangement also matters. Waterproofing is not simply a loose coat covered in an impermeable liquid.
Slide 3
Trapped air slows heat loss
The feather covering can retain insulating air near the body. That layer reduces the rate at which the penguin loses heat.
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Conditions change during a dive as pressure increases and air is compressed. Life in water therefore tests the coat differently from standing in cold air at the surface.
Slide 4
Renewing the coat usually keeps penguins out of water
Penguins replace worn feathers during a concentrated moult. They generally remain out of the water while their protective covering is renewed.
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Stored body reserves support this interval without normal marine feeding. The timing of moult fits the annual schedule, linking feather maintenance to earlier opportunities to accumulate energy.
Slide 5
Chicks need swimming plumage before entering the sea
A young penguin's downy covering differs from the swimming plumage it later develops. Readiness to enter water depends on development, not only size.
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Replacing down with suitable feathers is part of becoming independent. A large-looking chick can still depend on adults while its body and behaviour are not yet prepared for marine feeding.
Sources
- Penguins
British Antarctic Survey
- Emperor penguin breeding cycle
Australian Antarctic Program