Sleeping for Minutes with Others
Unlike humans, penguins never really fall asleep. Because they are often prey for predators such as leopard seals and Galapagos sharks, they have to constantly remain alert and on guard. Therefore, rather than going into a deep slumber like most other animals, penguins take several short naps throughout the day. On average, these naps last only minutes. For added protection, penguins can usually be found sleeping in groups (or rather, a rookery, as a group of penguins is called). These close sleeping arrangements not only provide security, but also supply additional warmth for the already well-insulated bird species.
Napping in the Ocean
While penguins have been observed sleeping only on land, since they are often at sea for periods of up to nine months, most scientists assume that penguins also nap while they are in the ocean. Although the time of day penguins take their naps varies, many scientists believe that, the late afternoon or early evening is the best time for them to nap, as they have finished their final meal of the day. Like humans, penguins appear to enjoy a more peaceful rest if their stomachs are full.
Many people believe that all penguins sleep standing up, however, this is not necessarily true. Out of the 17 different species of penguins, Emperor Penguins are most frequently seen standing up. Although it probably does not sound at all comfortable to us, there actually is a very logical reason for this unique sleeping position. By standing up, the Emperor Penguin, which lives in an extremely frigid environment, does not come into contact with the cold ground. Instead, only its well-insulated feet are subjected to the harsh chill. In fact, the penguins actually place their weight on their heels, so their toes do not even touch the ground. Then, in yet another clever move to stay warm, a penguin often places its beak under its wing in order to maintain its body heat.
In addition to standing, penguins can also be found in a wide variety of sleeping positions. King Penguins and other large species are known to sleep on their bellies, whereas smaller penguins often nap in burrows. When incubating their eggs, however, most species will remain standing. Just like humans, each penguin sleeps in the position that he or she finds safe, comfortable and warm.