Why Do Spiders Curl Up When They Die? The Full Answer

Ok. Why do spiders curl up when they die? This is one of those questions that you might have never asked yourself. You just quickly dispatch of that eight-legged thing that’s been crossing your territory and that’s it, be gone with it.

You’ve probably noticed, though, that spiders curl up after you kill them. Why? Why wouldn’t you want to know that? Well, wouldn’t knowing that be awesome? Like you’re together with a bunch of friends and talk about everything and nothing and you just tell them this. However, let’s see why spiders curl up when they die!

Why do spiders curl up when they die – The main reasons

A spider has eight legs, right? These legs shall have flexor muscles to help them contract their legs and extensor muscles to aid them extend their legs back out. Well, apparently, they only have flexor muscles. God thought of something else to replace the extensor muscles, a hydraulic system. Wait, what? Yeah, right? God had some pretty awesome ideas.

Well, in order to extend their legs out, spiders use the blood pressure spike from their heartbeat. To be more explicit, blood is pumped into the legs when they need to extend them back out as flexor muscles relax. Then, the flexor muscle contracts and blood pressure is relieved. They do this over and over again as they walk, run or even jump. A jumping spider can jump 25 times its body length. Can you believe that? But that’s a different article for another day.

So, why do they curl up and die? It’s simple. When they die, there is no more hydraulic pressure to extend their legs. The flexor muscles revert back to their original length and this is why the spider legs curl up.

Another awesome fact about spiders is that they don’t bleed. You probably happened to see a spider lose a leg and no sign of any kind of fluid coming out. This is strange, right? Because spiders have an open circulatory system that enables blood to flow freely through the body, no blood vessels involved. This means that a little wound could prove fatal to the eight-legged being. Well, no. God thought of everything, apparently. Spiders have a special mechanism that immediately seals off the leg that has been cut off and no loss of pressurization happens.

Here’s a short video basically explaining what we just wrote about above:

How awesome is this? Spiders are very unique creatures