Have you ever seen footage of penguins walking around in the cold wind and wondered why they seem so comfortable in temperatures that would quickly freeze human skin? Would you believe penguins are so well adapted to life in cold places they have a more difficult time dealing with warm temperatures than they do with cold?
How do penguins stay warm? Other birds grow feathers only in narrow tracts and then fluff them out to cover the rest of their bodies. Penguins, in contrast, have dense, scale-like feathers with downy tufted bases tightly covering their entire body. Underneath the many feathers, penguins also have a thick layer of fat that insulates them from the cold. Even though they live outside in extreme cold, the 101°F (38°C) internal body temperature of a penguin is higher than the average human body temperature.
Imagine yourself wearing several thick sweaters, a couple pairs of sweatpants, a wool hat, mittens, and a big puffy coat with the hood cinched down tightly. Now think about walking into a heated room and you might start to have some idea what it must be like to be a penguin in warm temperatures. What would you do if you started to overheat? Penguins can’t take off their coats, but they can try to lose heat through their feet, the only part of their bodies not covered in feathers. Penguins have many blood vessels in their feet and can send warm blood out into their feet to cool it down before it is pumped back into their body core. Before penguins dive into the cold water they can squeeze the blood out of their feet to keep from losing too much heat to the water. This explains why the feet of penguins that just jumped out of the water are white, but the feet of penguins nesting on land can be rosy.
Not only do penguins rely on cold temperatures to stay comfortable; they also rely on cold to maintain the sea ice they use for hunting, resting and, for the Emperor Penguin, making colonies for raising young.