Arachnophobia affects roughly between 3.5 and 6.1 percent of the world's population (which is nearly half a billion people) and is a pretty understandable fear.
They're creepy, they hide in the cracks of your home, some are deadly, they've got eight beady little eyes and some can take down prey that is much, much bigger than itself.
The fear of arachnids can come from a variety of reasons: a particularly nasty encounter or watching too many spider related movies. However, a new study suggests that you might freak out because it's hereditary.
Researchers from the Max Planck Institute for Human Cognitive and Brain Sciences and the Uppsala University have delved into whether arachnophobia is a learnt or inherited trait. The scientists found that children as young as six months old stressed out about a spider or snake, despite having had no or very little experience in them.
Lead investigator Stefanie Hoehl says: "When we showed pictures of a snake or a spider to the babies instead of a flower or a fish of the same size and colour, they reacted with significantly bigger pupils.
"In constant light conditions, this change in size of the pupils is an important signal for the activation of the noradrenergic system in the brain, which is responsible for stress reactions.
"We conclude that fear of snakes and spiders is of evolutionary origin. Similar to primates, mechanisms in our brains enable us to identify objects as 'spider' or 'snake' and to react to them very fast.
"This obviously inherited stress reaction in turn predisposes us to learn these animals as dangerous or disgusting. When this accompanies further factors, it can develop into a real fear or even phobia."
It makes sense to have developed a negative predisposition to these things considering we've shared the earth for a few hundred thousand years.
This theory is supported by Dr Ross Menzies from the University of Sydney, who has told the Independent: "It is a biological fear which can occur during normal development and doesn't go away.
"This 'fear' would have entered the gene pool because in certain areas of the world there are dangerous spiders and fear of them would be a good thing."
It's probably not the worst thing to be on the cautious side when approaching spiders because it's better to be safe than sorry.
To put you at ease, there are about 43,000 species of spider in the world (that's not the calming statistic) but only about 30 are known to have killed humans - which is less than one-tenth of a percent.
But if you're wondering 'why' when you see a web or it's terrifying fangs and you don't know exactly what sparked this fear, you can blame your parents, and their parents and their parents and so on.
Featured Image Credit: PA