Crouching Tiger, Hidden Spider

Willa (Menemerus semilimbatus). Betsy Mason Jumping spiders can see as well as house cats — despite being less than 10mm long in most cases. I find this astounding, but people almost never seem as impressed as I think they should be when I tell them this. Perhaps they don’t believe it could be true. It is, though. Scientists have measured these spiders’ spatial acuity, and it is on par with cats, pigeons, and elephants. Let that sink in for a moment. Jumping spiders can comfortably fit on your fingernail, while elephants are around 80 times bigger than you are. As I reported a few years back for Science News, your own visual acuity is only around five or ten times better than a jumping spider’s. “Given that you can fit a lot of spiders in one single human eyeball, that is pretty remarkable,” animal behavior researcher Ximena Nelson, who studies jumping spiders at the University of Canterbury in Christchurch, New Zealand, told me. “In terms of size-for-size, there’s just no comparison…