Lunch with a Jumping Spider

I think about jumping spiders a lot. If you have had a conversation with me in the last several years that lasted more than 5 minutes, you already know this. A friend once bought me a mug with a spider on it that reads “Sometimes I wonder if jumping spiders are thinking about me too.” The spider has a little thought bubble that says “Betsy.” 

I literally wonder this very thing, nearly every day. I may never know for sure, but I recently got a little closer to the answer, thanks to a clever new study. 

As I wrote in a previous post, I recognize individual jumping spiders in my neighborhood, based on where they hang out, how they look, and most importantly, how they behave. On my daily dog walks, I’ll often see the same spider on the same succulent for days and even weeks. 

Some are consistently curious and will let me get very close and take lots of photos. Some like to jump on my phone or my hand if I offer a slightly higher perch. (Before they jump they stretch their front two legs out toward their destination for a second or two, like a toddler asking to be picked up. It’s adorable.) Other spiders are quite timid, ducking behind a leaf the moment they see me coming, and stay hidden as long as I’m there. 

A lot of jumping spiders will let me approach if I am careful, but hide if I move too quickly, or get too close, or stick around too long. It’s as if they are curious, but lose their nerve. It’s these spiders who make me wonder if they might eventually recognize me like I recognize them. There’s one such spider currently living on an aeonium around the corner from my house, a young Phiddipus johnsoni I call Frieda. Could she come to know I’m not a threat? Could we become friends?

I’ve thought about what recognizing me would require cognitively. Frieda would need to be able to remember something for at least a day. And she’d need to be able to use her memories to ascertain that I’m not going to harm her — she’d need to be able to learn. 

There is research to suggest that at least some jumping spider species are capable of both remembering and learning. Scientists in New Zealand tested the memory of Portia africana and found they could remember the type and number of prey items they had seen during trials that lasted up to 30 minutes. And they are able to learn exactly how to vibrate the silk of other spiders’ webs to trick them into coming close enough to pounce on them.

Portia species are known for being particularly clever jumping spiders, but let’s give Frieda the benefit of the doubt and assume she can remember and learn too. 

So far so good. But there’s one more requisite ability: Frieda will need to recognize me. How plausible is that “Betsy” thought bubble? 

Jumping spiders have astonishingly good vision. Their two primary eyes have boomerang-shaped retinas that curve toward each other such that the center of the boomerangs can overlap. In that little spot, jumping spiders have color vision and can see with the range and acuity of a house cat. A cat! In case you have forgotten, these spiders are often just a few millimeters long. I’m not even going to try to do the math on how much smaller they are than cats. So I’m pretty sure Frieda has the physiology to see me in enough detail to distinguish me from the rest of the (mostly) spider-hating humans out there.

Still, jumping spiders are generally not social animals. Outside of courtship and territory defense, they are mostly solitary. So it’s unclear if there’s any reason for a jumping spider to be able to recognize other individual spiders, let alone members of other species. 

Many mammals, such as dogs, can clearly recognize different humans. The same goes for cats, cows, and chickens. Crows have been known to remember individual people for years (and to hold a grudge against those they see as a threat). All of these animals are social creatures who need to keep track of relationships with other individuals in order to thrive. Jumping spiders do not. 

This brings us to the new research. A study published in November found that jumping spiders can indeed recognize other individual jumping spiders. 

Here’s how Christoph Dahl and Yaling Chen of Taipei Medical University tested Phiddipus regius (a.k.a the regal jumping spider, and a relative of Phiddipus johnsoni spiders like Frieda and Diego). They set up “face-to-face” meetings between spiders (separated by a clear acrylic sheet), and watched how they reacted to each other during a 7-minute trial, measuring the amount of time they spent near each other as a proxy for interest. The first time a pair of spiders met, they typically approached each other. They then had a 3-minute break before their next encounter. If the same two spiders met again, they stayed further apart. But if after the break, there was a new spider instead, they would come closer. 

Three dozen spiders showed this same reaction over many trials, growing less and less interested in the familiar spiders. But even after many rounds of testing, a new spider would elicit renewed interest. The spiders were able to recognize which spiders they had seen before and which were new, even after hours of being presented with different spiders.

While I am not entirely surprised by this, it is, scientifically speaking, a very surprising result. There is a long-held assumption in the field of animal cognition that complex mental abilities are the exclusive purview of animals with spines, large brains, and complex social lives. A leading hypothesis is that it is precisely the demands of being social that necessitate more cognitive capacities. Because complex cognition requires a lot of brain power, which requires a lot of energy, the thinking goes, animals wouldn’t evolve these abilities if they weren’t getting a huge social benefit from them. 

But evidence has been accumulating that small-brained invertebrates are capable of some pretty impressive mental feats. Bees are a great example, as are jumping spiders. 

Research has also shown that paper wasps are quite good at identifying the faces of other individual wasps, and can keep those faces in memory for at least eight days. This makes some sense because these insects are also social animals. Jumping spiders are not.

Which is why the new study is surprising. “These findings invite a shift in perspective,” Dahl and Chen write. “If a tiny, mostly solitary spider can recognise individuals, how much brain is really needed for flexible social memory?”

Jumping spider brains — which are the size of a poppyseed — may be capable of far more than we thought. “We may underrate animals with compact nervous systems because we treat brain size as a stand-in for cognition,” the authors write. “What do such abilities imply for debates about animal consciousness? Behaviour cannot prove subjective experience, but it narrows what kinds of minds are plausible.”

More importantly, what does this imply for me and Frieda? I may just be seeing what I want to see, but I think she’s already grown less afraid of me. I’ve worn the same fleece on my visits the last several days, in case that helps her remember me. Today she spent several minutes tracking me and waving her pedipalps as I moved around. Then she started to back away, so I gave her some space and hung out with the spider on the aeonium next to hers for a bit. 

When I returned, Frieda sat still, watching as I slowly reached my finger toward her until it was just an inch away. I took a photo to capture the moment, and when I zoomed in to see if it was in focus, I noticed that while I was away, Frieda had caught a fly. Perhaps I’ll bring a sandwich when I visit tomorrow, and see if we might have lunch together.

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