Why do Penguins not wear socks?

Why do penguins not wear socks? I must admit I borrowed this title from one of our twelve extraordinary expedition crew members who educated and guided us during our Antarctica expedition. Let me digress here a little bit because for me this was a highlight of the trip – the caliber and high level of expertise of the expedition crew which made the trip even more educational than I had expected. Maricel, for example, is from Argentina and has a degree in Biology. She was our bird expert since she researched Skuas for 4 years and now lives in Patagonia where she expanded her research into ecology and conservation issues. She is regularly visiting Antarctica on trips such as ours. Not only did these experts give lectures on their area of expertise, but they also accompanied us on all of our outings as some of them were our Zodiac drivers.   

Back to the topic at hand. Hopefully you don’t mind me geeking out a little bit. First off, there are 18 different species of penguins around the world but only six live in Antarctica, of which we saw three, the gentoo, the chinstrap, and the Adelie penguin. So why do the Antarctic Penguins not get cold feet waddling all over the ice and snow? There are two main reasons: First, their feet and lower legs are mostly tendons, bone, and a thick layer of skin and most of the muscles that provide the mobility are higher up in the body covered by fat and feathers. That makes all sense, doesn’t it? But the second part was more surprising to me: The blood vessels to the penguins’ feet can be constricted to limit blood flow to their feet when it is really cold and opened up when it is warmer. That in itself is not that unusual, but moreover, the up- and down-flowing blood vessels are intertwined to provide an heat exchange so that the blood going to the feet is colder but the blood flowing back to their body is warmed up so their body’s core temperature does not get cooled down as much from cold blood coming back from their feet. Isn’t that amazing? That’s why they don’t need socks! 

Penguins are birds that don’t fly and actually spend most of their lives in the water. Only to mate, nest and raise their chicks they congregate in a "waddle" or “rookery”. Did you know that when you encounter a group of penguins in the ocean, they are called a “raft”? They like to play, wash themselves, but also find food, of course, mostly a mix of crustaceans, small fishes, squid and krill, depending on the penguin species.  

Penguins create these “highways” which they use to travel from the rookery to the ocean and back. After a while, depending on the snow and ice conditions, that highway can become quite deep. In order to be respectful of the animals and they environment we were instructed not to block or step on to such a highway, we were also instructed not to get closer than 5 m (about 15 feet) to a penguin, but that it is alright to let them come to you. And they do, because their curious little animals. The red on the penguin’s feather is not blood. It is from excrements that turn red from the krill they feed on. 

Most of the time we saw  Gentoo penguins but there were also Adelie penguins (our expedition guide Eduardo said they have psychedelic eyes) and Chinstrap penguins. The latter are easily spotted as they look like they are wearing WWI helmets with chinstraps. Those three kinds of penguins are very closely related to each other, so you sometimes see them mixed up in rookeries. Gentoos can be 20-35 inches tall, and they are fast underwater swimmers.