What does it mean to be a jumping spider?

Have you ever wondered what it means to be a jumping spider?  If you're like most people, then the answer is very likely no.  If, however, you are one of those rare souls who have pondered such a point, then I say good for you!  Either way, today's post will focus on jumping spiders and what makes them so special as a family of spiders.

First and foremost, as with many rules in science there are exceptions. Today, however, we will stick to the traits common to most jumping spiders.

Jumping spiders are unique in several ways, but our focus will be on the three biggest differences that set them apart from other spiders. These differences are:

1. No webs
2. Excellent vision
3. Very smart

No webs
Unlike most other spiders, jumping spiders do not spin webs for prey capture, but rather hunt them like miniature, eight-legged cats.  They do still produce silk, and it is used in hunting, but not for prey capture.  Rather, they use the silk as a safety line, similar to a rock climber's rope.

Dragline and attachment point on glass. (Frank's Photo Essays)

The dragline ensures that when they jump, either after a prey item or to cross a gap, they have a backup if they miss.  Salticids also use silk to make retreats (the spider equivalent of a sleeping bag)
and for egg sacs, which are usually deposited in the females retreat.

Salticid in retreat. (Brisbane Insects and Spiders)

Excellent Vision
Jumping spiders have quite excellent vision which they use to find and stalk their prey.  They are able to see a broad range of colors, and some even in UV!  While they can see at a fairly high level of resolution, it is not quite as good as ours. Also, how they process things visually is a bit different from humans as well.  Here are two examples that might help you better understand their vision. Please bear in mind that the examples are only approximations.

Example 1:
Jumping spiders see a lot detail, but not as well as us.  If we see in 1080p, then a jumping spider sees what a normal television would display.  Compare the two pictures below, one in "Human vision" (High res) and one in "Spider vision" (Low res). 

"Human vision" vs. "Spider vision" (Borrowed from Wedding by Color)

Example 2:
To get all of the detail that they are able, jumping spiders sacrifice the speed of image acquisition.  In other words, when you look at a picture, you see it all  at one and process it almost instantly.  Jumping spiders, on the other hand, have to process things line by line.  I often use the comparison of a cable modem versus an old dial up 28k modem.  If human vision is high-speed internet, then jumpers are confined to the slow, but effective world of dial-up. 




Very Smart

Jumping spiders are able to do some very interesting and complex behavior considering their tiny size and even tinier "brains". Some of the more interesting things we've discovered these little predators can do include planning routes to prey items, trial and error learning, adaptive hunting techniques that vary based on previous experience with prey items, and my own research suggests that they are even capable of learning about something just by watching it.  Pretty amazing considering the brain of most of these little guys is smaller than the head of a pin!

So remember, the next time you see one of these fascinating little creatures, think twice before you decide that it needs to meet the bottom of your shoe.  The life you spare may just make your own more interesting