If you have clicked onto the Tennessee Aquarium’s penguin cam at the right time you’ll observe our birds resting. But they don’t really go to sleep like humans, they tend to go into a longer period of napping without falling into a true deep sleep. Penguins have a natural instinct to always be on guard against any lurking predators wherever they may be. That’s another reason why they sleep fairly close together at night so there’s less of a chance any one bird being taken off guard. You’ll also notice that our penguins sleep in several different positions. It is perfectly normal for gentoos and macaronis to rest or sleep on their bellies. They also sleep while standing, sometimes with their beak tucked under their wing which helps regulate heat loss. Another interesting way I have seen them sleep is when they roll onto the back part of their foot bringing their toes off the ground. This helps regulate heat loss by keeping their toes off an icy or cold surface. Late in the afternoon after their last feeding of the day they tend to start preening. With full bellies, they go into a restful mode. But even in the middle of the night, you’re apt to see one or more penguins swimming or waddling around while everyone else is sleeping.