South African Safari Mysteries - How Do Giraffes Sleep?
This is the kind of question that comes to you deep in the night on your South African safari, when the sound of a lion roaring wakes you up.
You sleep like a log in your luxury safari accommodations, but how do the prey species 'out there' manage it. Especially the less agile ones like giraffes. These ungainly beasts aren't exactly designed for curling up under a bush or jumping up rapidly.
The short answer is 'giraffes sleep on their feet – with one eye open'
Like most prey animals, giraffes cannot afford to let their guard down for a moment. It doesn't matter that they are quick enough to outrun most predators on a good day, or that they can punish any takers with a powerful kick. Giraffes are afraid of being eaten, and rightly so.
Like horses and cattle, giraffes can lie down, but they choose not to. You may be lucky enough to catch sight of a youngster lying down with its head tucked towards its tail, but it's an unusual sighting indeed.
Adult giraffes hardly ever hit the deck come nap time – and nap they do. Giraffes sleep for about 4 hours a day in short bursts of about 5 minutes at a time. Like mallard ducks and chickens, they have been observed sleeping with one eye open, although they usually close both.
In an environment where they feel safe, such as a zoo or reserve without any predators, giraffes have been seen to lie down and sunbathe or sleep. These instances are rare though. Their large frames take a long time to get upright again and they are designed to stay on their feet as much as possible.
In order to stay upright during slumber, giraffes are able to align their legs vertically and lock their knees and hocks into position. These adaptations require very little muscular effort to keep the animal from falling over.
Anyone who has dozed off in front of the telly will know that the first thing to go south is your head. The strong muscles and long vertebrae in the giraffe's neck prevent this from happening to them. While their heads may droop a little lower while they are asleep, they don't plummet earthward as ours do.
Scientists hypothesise that giraffes may also sneak in a few extra winks by dozing as they stand ruminating. Unfortunately, it is still scientifically difficult to measure exactly what giraffes get up to in the wild.
Nature is full of mysteries. One of them is why herbivores are adapted to sleep so little when everybody knows that lions sleep for about 20 hours a day?
Now that's a question for your ranger on your next South African safari.