It seems like few of us ever get as much sleep as we would like. Between work, family and social obligations, the hours of the day seem to slip away before we know it. Sleep, however, may be one of the most important things we can do for ourselves. Scientists think it offers our bodies a chance to form new memories, recover, heal and even grow. The human body can actually survive longer without food than it can without sleep. When all is said and done, the average person spends nearly one-third of their lives sleeping. Humans aren't the only ones. All mammals, birds and many other animals also need sleep to stay healthy, but they don't all do it in the same way.
The brown bat is a champion sleeper. This animal spends almost 20 hours sleeping every day! The bat probably needs all that time sleeping to recover from its hard four-hour nights. There is a very good reason that bats are the only flying mammals in the world — flying is hard work. In order to stay airborne, a brown bat will flap its wings 12 times each second or 720 times each minute. While flapping at an incredible rate (for a mammal), they must swoop and dive to snatch up to 1,000 insects each hour. Try that for a few hours and you will probably need a little extra sleep, too! And, of course, that is assuming that the bat is not a pregnant female. Imagine adding the effort of growing and birthing an infant that weighs 25 percent as much as you do. That is equivalent to a 150-pound human giving birth to a 37.5-pound baby — no small feat.
Dolphins, whales and other aquatic mammals have evolved a method of sleeping even more unique than hanging upside down from the ceiling. We've all heard of sleeping with one eye open, but these animals take that adage to a new level. Many aquatic mammals sleep with only half of their brain at a time. For most land-dwelling mammals, breathing is neither voluntary nor a conscious effort. We are surrounded by air and can take it in however and whenever our body needs it. This is not true for aquatic mammals. Dolphins and whales are conscious breathers; this means that each time they rise to the surface for air it is because they have made the voluntary decision to take a breath. If these animals fell asleep as fully as we do, they could forget to breathe and quickly drown. Instead, these animals sleep with only one hemisphere of their brain at a time. While the right side of the brain is asleep, the left can stay alert for danger and remind the animal to surface for air. Eventually, the roles will reverse and the left side will have the opportunity to sleep while the right side stands watch.
Finally, one of the shortest sleepers in the animal kingdom is the giraffe. These animals average less than two hours of sleep each day, which is usually broken up into several five- to 15-minute naps. Losing sleep must be one of the disadvantages to sharing your home with lions. Here at the zoo, our giraffes don't have to worry about lions, but you still won't catch them laying down on the job.
Whether you prefer catnaps or long undisturbed hours, make sure you get plenty of sleep, then come visit the zoo to learn more about our unique and fascinating animals.
Visit our award-winning Web site at www.garden-city.org/zoo.