Every Animal Has to Sleep Sometime

Some species feature a brain that’s unihemispheric (one brain hemisphere sleeps while the other is awake). Sleep patterns are dictated by a combination of heredity and environment. Consider those of these creatures:

Having all your ducks in a row takes on a whole new meaning when you observe the sleeping habits of these waterfowl. When ducks are ready for a rest they line up in a row. The lucky ducks in the middle get to sleep soundly with both eyes closed.

However, the duck on each end of the row uses its single-hemisphere sleep mode, only keeping the one eye open that’s facing the outside of the line. These bookending ducks only get half the rest of the other ducks, but by standing guard over their fellow fowl and protecting them from predators, they increase their own survival.

Bats are pretty unique in that they sleep hanging upside down. It’s easier this way because it takes virtually no energy for them to hang from their strong, sharp talons which can grasp a variety of hard surfaces.

They‘re also energy-efficient when they want to fly-they drop from their hanging spot and take off into the air rather than pushing off the ground; compared to birds their wings are weak. These winged mammals are nocturnal, typically sleeping around 19 hours a day.

Giraffes sleep less than most members of the animal kingdom, typically dozing a maximum of two hours in the wild, and those hours are usually broken into much smaller segments throughout the day.

Weighing nearly a ton, giraffes don’t have an easy time standing once they’ve laid down, so they sleep standing up resting their head on their hind end. So, how do giraffes sleep standing up without falling over? They have a stay apparatus, which is the ability to lock their legs so that they don’t have to use their muscles to keep them upright.

Meerkats are African burrowing mammals related to the mongoose. Meerkats sleep up to a dozen hours a night. Since they’re pack animals they like to sleep together in a heap to conserve heat and maximize protection.

The matriarch of the group sleeps at the bottom of the heap so that she can get the most rest and be the best protected. There are also meerkats that act as “sentries,” lightly sleeping on the outside of the burrow to alert the others of potential predators.

Dolphins are a type of toothed whale. Like ducks, dolphins have the ability to allow one hemisphere of their brain to sleep while the other side stays awake. This means that they’re literally half asleep, keeping one eye open to watch for predators.

Due to their unihemispheric sleep capacity, dolphins can surface for a breath without being fully awake. At other times dolphins choose to “log” or sleep-float, remaining unconscious on the surface.

The Alpine swift is a highly migratory bird weighing just under a quarter-pound. These birds routinely fly for six months uninterrupted and have even been known to fly an astounding 10 months without a stop. These birds spend more of their life in flight than any other bird.

They don’t land on anything for the entire stretch-not to eat, drink or even sleep. When they reach appropriately high altitudes for gliding, they take short naps. Surprisingly, they’re still able to navigate even during REM sleep! They’re literally flying with their eyes closed.

Underwater, on land or in the air, all living creatures need a certain amount of sleep. They get it when they have the opportunity and in a manner that adapts to an ever changing environment.