What do we consider smarts?
For example, with some examples there, like pretending to do a mating ritual for another group of spiders in order to lure the female out, this seems like it's something built in to their neural networks through thousands of years of evolution. It doesn't seem significantly smarter than the other group of species doing mating rituals themselves. They just have a neural network that reacts to certain input with this output that evolution created and honed through all this time of them being around such input and this output causing a better survival performance.
I didn't see anything specific that could've indicated they could learn new things in new situations, so it seems like built in neural networks that come to them rather than them having special smarts to learn new things like humans have.
> Although spiders can’t literally count one-two-three, the research suggests some jumping spiders have a sense of numbers roughly equivalent to that of 1-year-old humans.
I wonder about conclusions like these. I don't know about 1-year-old humans, but it's understandable that they can measure strength levels depending on the amount of whatever they are observing and if situations change they should recalculate their new decision. I just don't think it's a sense of numbers, it would be more like some sort of amount of input (pheromones, image, whatever) that makes them pay attention that something has changed.
And all in all it seems odd conclusion to compare sense of numbers based on that to 1-year-old humans. Trying to compare it to something, but the way they use those "skills" doesn't really make comparative sense.