Sumipen's "change of clothes"

Hello everyone! With so many hot days recently, I'm sure there are many of you who have changed your clothes early this year. Just like us, penguins also have a time to change their clothes. The Magellanic penguins living at Sumida Aquarium go through the "molting" period in early summer. After the breeding season from December to May, which we introduced in a previous column, they begin preparations for this molting. In this column, we'll introduce you to this major summer event, "molting"! (Yamaguchi Maho, Exhibit and Breeding Team)

■What is molting?
Suddenly, take a look at this photo.

Both images are of the same penguins, Hydrangea; the left is a normal photo, while the right is a photo of the penguin molting, where all of its feathers are replaced. Its body is fluffy and looks different compared to the photo on the left. When a penguins regrows all of its feathers once a year, this is called "molting." This fluffy appearance is a rare sight that only happens once a year, and when I first saw a penguin penguins, I was amazed at how it was a size larger than usual and how its feathers were falling out so quickly!

penguins' feathers become damaged over time, and as they become fluffier and are no longer able to repel water effectively, this can interfere with their swimming, and as the feathers deteriorate and fall out, exposing the skin and causing injury. Molting is a very important event in the survival of penguins.

Now, let's take a look at how the Magellanic penguins at Sumida Aquarium go through their molting season.

■ First, prepare the body before molting
At Sumida Aquarium, the molting season takes place from June to October, including the preparation period.
June is the month when penguins and we are all busy preparing for molting! During molting, penguins use a lot of energy to make new feathers, so they eat a lot of food before the molting begins to store up nutrients.

Normally, each penguins eats about 10 horse mackerel per day, but before molting, they eat 30 to 40 per day! This makes feeding time even more hectic than usual! The penguins just want to eat! So they tackle other penguins to steal their food, or suddenly jump from a slightly higher rock. Sometimes, in their excitement, some of them mistake the animal care staff's hands for food and try to eat them (laughs). It really hurts when they mistake your hand for food and eat it.

If we compare their appearance before molting with their appearance during molting, when they have eaten a lot and stored up their feathers...

They look so plump during molting, you might wonder if they're really the same penguin! When I first saw a penguins molting, it looked just like a rice ball, so I couldn't help but take a photo of it, and it's still one of my favorites (lol). By eating lots of food and constantly storing nutrients in their bodies, they gain weight to about 1.5 times their normal weight in about two weeks. For example, in 2024, "Ajisai" normally weighs about 4kg, but by the time she starts molting, she weighs 5.5kg (about 1.4 times her normal weight!). I especially love the way penguins walk during this time of year when they've gained weight; they can't climb small steps that they would normally be able to climb, and their steps are heavier than usual. It's so adorable to see them working so hard to move their heavy-looking bodies. If you want to see these penguins in action, we recommend visiting around August!

■Currently molting <br />This is the hydrangea that we introduced earlier, which is currently in the process of molting.

They look as if they are patiently enduring something. During the molting period, they use a tremendous amount of energy to create new feathers, so it is also a time when they are prone to falling ill. During the molting period, as can be seen in the photo, their eyes look tired and they barely move. It is difficult to determine whether this is because they are molting or if they are genuinely unwell, so more thorough health management is required. During the molting period, we observe the penguins from even closer distances and interact with penguins with the utmost care so that we can immediately notice any changes in their health. The photo shown here is one taken at that time.

At Sumida Aquarium, we feed the penguins about one horse mackerel per day even during molting to keep them hydrated and to check their appetite and health, but in the wild, penguins cannot swim during molting, so they cannot eat at all.In addition, with new feathers growing under their old ones, it is difficult for them to regulate their body temperature, so they stay still on land during this period.

It takes about two to three weeks for all of the feathers to grow back. Before I actually saw a penguins molting, I thought, "Even if they're staying still, they'll walk around a little, right?" But when I saw the penguins standing there motionless, like Jizo statues, I found myself clasping my hands together and praying (laughs).

■What the animal care staff do during the molting season
At Sumida Aquarium, we review the records from the previous year and each year determine the target weight and care method that is best suited to each individual Magellanic penguins, so that all of them can complete their molt safely.We use a lot of trial and error, such as giving more food earlier than others to penguins that are prone to getting sick if they suddenly gain weight, giving different types of fish (sardines or silver-stripe herring) to penguins that have grown to dislike horse mackerel and are not gaining weight easily, and increasing the number of meals given to penguins that cannot eat a lot at one time.

To ensure that all the penguins are healthy during their molting period, we pay closer attention than usual to the condition of each one, looking at many different things, such as "Do the penguins' eyes look bad?" "Is their complexion normal?" "Do they want to eat?" "How do they eat?" "How often and how are they breathing?" "Is the color and smell of their excrement okay?" so that we can immediately notice even the smallest changes.

■It's not just their personalities! Even their molting has its own unique characteristics!
Immediately after molting begins, the feathers fall out one by one, but at the peak, they all fall out in a single felling, leaving the penguins's feet with a carpet of feathers. Each penguin has their own unique way of shedding, and no two feathers shed in the same way. From here on, I'd like to introduce some of my favorite molting fashions!

① "Sakura"

Only the top of its head still had feathers that hadn't fallen out, making it look like a topknot! I couldn't help but take a photo!

② "Anko"

This one only has feathers around its neck, making it look like it's wearing a scarf! So stylish! And the smug expression is irresistible.

3. Melon

The feathers remaining on its back look like a heart! So cute!

■After molting

Once almost all of their feathers have grown back, the penguins finally return to their usual pool. On the left is Daifuku, who looks proud of his shiny new feathers, and Cherry, who has almost finished molting.

The first time I saw a penguins that had just finished molting, I was surprised to see that its newly grown feathers were "silver-ish"! They were shiny and shining, and looked divine! Around September, you can see lots of penguins swimming around with their shiny feathers!

What did you think of our introduction to the penguins during the molting period? They eat even more frantically than usual, gaining weight, and swim with shiny feathers that are unusual for a post-molt period... During the molting period, penguins show off many different sides to their usual selves. If you think, "penguins that have gained weight are so cute!" or "penguins that have finished molting are so divine!", then please come and meet the penguins during the molting period! And we would be very happy if you could watch over the penguins as they work hard to molt together with us, the animal care staff !