Spiders are disgusting, dangerous, frightening. That is what most people think of them and therefore countless harmless and useful spiders are killed. With a few exceptions the many species of spiders which occur in Namibia do not cause any harm to humans. The large spiders in particular are more harmless than their appearance and reputation.
Selenopidae, known as wall spiders and flatties, have a diameter of up to 5 centimetres and are extremely flat. They are often found in buildings, where they rapidly scurry across the walls in search of food or cover. Many people are afraid of these spiders and kill them, even though they are completely harmless for humans. Instead, they make short work of mosquitoes, flies and other pests.
These spiders are very intriguing because their running and striking speeds place them among the world’s fastest land animals. If an insect lands or runs next to a wall spider, the spider spins around so fast that a fly or a mosquito has no chance to take off. A wall spider manages three pirouettes within the blink of an eye. A world record!
Roman or sun spiders (Solifugae) also instil fear. Some species of this order are orange and hairy and almost the size of your palm. They are often mistaken for tarantulas. Roman spiders also called solifuges, however, are not true spiders, because they have no venom glands and no spinnerets to produce silk. And they have chelicera, i.e. pincer-like claws, instead of claws for biting. In relation to the size of their body, camel spiders boast the most powerful biting tools in the animal kingdom. Another world record! With their double chelicera, which can also move sideways, they mince their meals of insects, spiders and small reptiles. I have seen a sun spider crush muscles and bones as it fed on a still fresh dead mouse.
Many are afraid of baboon spiders, such as the Namibia horned baboon spider (Ceratogyrus sanderi), because these hairy, mostly dark spiders are considered to be particularly dangerous. The truth is that baboon spiders are afraid of humans and try to retreat as quickly as possible when we approach. Baboon spiders in Namibia are also harmless, but like roman spiders they can inflict a painful bite. It is amazing that nevertheless countless baboon spiders – called tarantulas in the Americas – are kept as pets all over the world. No spider ever attacks a human.
Especially in the rainy season the banded-legged golden orb web spider (Nephila senegalensis annulata) can be spotted outdoors as it spins its web between shrubs and then sits in the middle waiting for prey to get entangled in it. The black and yellow spider is a female if it has a body length of about four centimetres; the males are much smaller, usually less than a centimetre. These spiders are also completely harmless to humans, but some people get a fright when they suddenly feel the cobwebs on their faces while walking in the bush.
The big spiders of the Namib Desert behave in the most intriguing ways. They are rarely encountered, however, because like many of the large spiders they are nocturnal. The Namib spiders are very light-coloured, not least because they spend the day in burrows in the sand which they construct themselves. When detected with a torch, one of the spider species may be seen communicating with conspecifics by tapping its foremost legs on the ground – which is why this species is called dancing white lady (Leucorchestris arenicola).
Another one has developed a unique way to escape from enemies. In the face of danger the wheeling spider (Carparachne aureoflava), or golden wheel spider, will fold its eight legs to its body, flop onto its side and cartwheel down the steep dune slope with lightning speed. It will then look for suitable shelter at the bottom of the dune.
Author: Dirk Heinrich