All birds molt, or lose feathers, on a yearly basis. Some birds molt a few feathers at a time, while other birds, such as penguins, molt all of their feathers at once. The total process generally lasts between 4-6 weeks.
Imagine having the same sweater on for one whole year…during this time, it might become worn out and need to be replaced. This is essentially how penguins’ feathers work. Their feathers become worn out and broken over the course of the year and it is necessary for a new set of feathers to replace the old set.
There are 3 stages to molt:
- Dropping feathers
- Gaining weight back
1. For several weeks leading up to molt, penguins begin gorging themselves with fish. Generally, a penguin will eat approximately 1lb of fish each day. Leading up to their molt, a penguin can eat up to 40% of their body weight daily. These extra calories allow new feathers to be produced under their skin. A penguin usually weighs 7-8lbs, but after bulking up pre-molt, they can weigh up to 11lbs.
2. Once the penguin has reached their maximum weight, they begin to drop feathers. This process generally lasts 1-2 weeks. During this time, the animal is fasting (not eating) and allowing all the feathers to drop off its body while the new feathers come through. They must remain on land during this process due to their lack of waterproofing. They live off their body fat stored from the previous weeks.
3. The last part of the process, which entails the penguin’s body recovering, lasts another 1-2 weeks. During this time, they gain waterproofing once again on their feathers and begin hunting fish to regain all the weight lost.
Molting generally happens once a year at approximately the same time for each bird (typically between April-Aug). So the next time you see one of us looking a little puffy and uncomfortable, don’t worry, we are just updating our wardrobe. Soon we will be ready to show off our new sleek, shiny new coat of feathers.