If you can leap up to 50 times your body length, you’re not going to get trapped in someone’s bath.
Before you panic, the jumping spider isn’t after you, and the world’s biggest, Hyllus giganteus, is a whopping 2.2 cm (0.84 inches) long. Also, although I’m standing by my rule of no bug photos, today’s arachnid has two adorably huge eyes, floofy hairs on its head, and is usually very colourful, so do click here if you’re feeling brave. Why is this spider like this? Is it another ploy to infiltrate our homes and terrify us forever more? Or is it the closest some of us will ever get to liking one?
The eyes have it
Found on all continents except Antarctica, the family Salticidae has about 5,000 energetic little members seeking out tiny bugs and pouncing on them or out of danger accordingly. Hunting in broad daylight means vision is key, and thanks to the two huge puppy-dog eyes at the front of their head, jumping spiders can see almost as well as humans.
While these two eyes deal with acuity, the other six around the rest of their heads focus on motion, with the rear set topping off a near-360 degree awareness. Their vision is thought to be so good that according to some researcher anecdotes they not only recognise their human carers, but can be alerted by waving.
Not impressed? How about this: it takes human babies up to five years for their vision to reach the same level of detail as an adult’s. A baby jumping spider has that from the word go, with all 8,000 adult photoreceptors already in place, just smaller.
Excellent eyesight is useful when you’re a mimic.
Some species, like Myrmarachne melanotarsa, mimic ants. Not so they can secretly munch on them and their children, but rather benefit from colony protection and the ants’ own pantry, including honeydew. In fact, this jumping spider has more to lose, because its own eggs and juveniles run the risk of being ant food. It also sportingly avoids or tolerates other jumping spiders with the same idea, like the Pseudicius or Menemerus lot, with some reports showing colonies of 50 or more. However, while it can appear slightly more social than other spider species, this may be for protection or a calculated risk.
The other type of creepy
While on the whole jumping spiders have ditched the web – because who stays in one place with such an awesome mode of transport – they do sometimes congregate in a nest, either in winter, or to increase their chances at romance.
Sometimes a male jumping spider will pitch up next to the nest of a subadult female, lie in wait, and as soon as she’s finished her moult and tipped into adulthood, try his luck. Some Phidippus johnsoni females didn’t seem to be swayed, but it’s a common tactic among jumping spiders. When you hear about their courtship, you’ll understand why.
Sure, you’ll probably get a date. Of death.
It’s a cliché by now, but spiders aren’t above munching on their fellow neighbour, or even their current or previous partners. This doesn’t happen all the time, but in some species, a female will pounce and devour her suitor if he didn’t perform the correct courtship dance, possibly because she misidentified him as prey, although I’m not convinced given their eyesight. I say “correct” courtship dance because not only are they very specific, there’s more than one.
Depending on where the female is, the male jumping spider needs to play his cards right. If she’s outside her nest, it’s all about the bright colours and fabulous dance moves. Don’t think a spider’s up to it? Well Phintella vittata can see UVB light and when the males reflect it off their bodies, it gives them an edge in the dating game. If that’s not glamorous enough, how about the stunning peacock spider, whose courtship was only filmed for the first time in 2011?
If the female’s inside her nest, on the other hand, tugs and vibrations are the way to go (fnar) so she can feel it through the web. But when jumping spiders assemble for love, it can quickly turn to war, with male-on-female, female-on-female, and male-on-male cannibalism also a possibility, especially if a back is turned. So being able to leap out of harm’s way is pretty useful, bringing us to the main thing that sets these little arachnids apart.
Performance under pressure
If you were brave enough to look at the photos or video (I’m not counting my drawing as a reliable source), you may have noticed that jumping spiders have skinny legs. So how do they leap so far?
Simple. We think they force blood into their legs at extremely high pressure, helping propel them forwards. They’re full of high pressure fluid, it seems, making their entire bodies leap apart in opposite directions whenever researchers try to poke or attach anything to them.
In case their attempts at leaping also take a dark turn, jumping spiders fling two safety ropes of silk out behind them, and use their front-most eyes to help judge distance.
So they’re dainty enough not to look horrifying, and if you got up close, you’d see a big pair of innocent eyes staring right back at you, probably remembering your face if you’re kind enough to give them food. Their striking colours and patterns can also make you forget they’re spiders. It must be evolution: if they were big and spidery-looking, they’d be extinct and the world would be out of flamethrowers before we even knew its name.
Latin: Family name is Salticidae.
What? Any of 5,000 spider species that pounce on their prey.
Where? Mainly in the tropics, although some species are known from Arctic regions as well.
How big? The largest, Hyllus giganteus, is only 22mm / 0.86 inches long, so fret not.
Endangered? There are thousands of species, in large ranges and different habits, however, a small handful around the Seychelles are endangered according to the IUCN Red List.
Probable motto: I look cute and keep out of your way. I’m the perfect spider!
They almost look adorable. Do they need my help at all?
Spiders usually fall to the bottom of the list in terms of conservation, but I did find a couple of helpers on my travels:
Buglife looks out for the interests of the distinguished jumping spider (yes that’s its full name), and the British Arachnological Society promotes research and understanding of our eight-legged cohorts.
Just to prove I’m not fibbing:
BBC Earth Unplugged. 2016. “Watch the world’s biggest jumping spider make a leap“. BBC.co.uk.
Cockburn, Harry. 2018. “Rare jumping spider discovered in UK for first time ever“. The Independent.
Editors of Encyclopaedia Britannica. No date. “Jumping spider“. Britannica.com.
Geggel, Laura. 2014. “Creepy: peering into spiders’ brains without exploding them“. LiveScience.
Goté, John et al. 2019. “Growing tiny eyes: How juvenile jumping spiders retain high visual performance in the face of size limitations and developmental constraints“, Vision Research 160:24-36.
Grrlscientist. 2013. “The extraordinary courtship dance of Australia’s peacock spider“. The Guardian.
Hadley, Debbie. 2019. “Jumping spiders: habits and traits of the world’s expansive spider species“. ThoughtCo.com.
Jackson, Robert R. 1980. “Cannibalism as a factor in the mating strategy of the jumping spider Phidippus johnsoni (Araneae, Salticidae)“, Bulletin of the British Arachnological Society 5(3):129-133.
Jackson, Robert R. et al. 2008. “The natural history of Myrmarachne melanotarsa, a social ant‐mimicking jumping spider“, New Zealand Journal of Zoology, 35(3):225-235.
Nield, David. 2019. “Baby Jumping Spiders Are Watching Us, Their Eyesight Is That Good“. Science Alert.