One small leap for the jumping spider but a giant step for vision science.

Weasels may be cunning, we might admire the intelligence of dogs and cats, but we can be forgiven for expecting the jumping spider, a diminutive predator with a brain not much bigger than a poppy seed, to be one of Descartes’ automatons. Yet, jumping spiders, also known as salticids, alternate between entertaining and alarming us by planning prey-capture tactics ahead of time, adjusting their hunting behaviour in accordance with how the prey responds and giving us other examples of un-spider-like acumen (reviewed by Harland and Jackson, 2004). Underlying salticid behaviour, there is a more basic defiance of common sense. We may think that spider-size eyes are simply not suitable for seeing a lot of detail, but salticids seem to be telling us to think again. Here we have a celebrated example of how seeing with high spatial acuity can be achieved at a high level by a lowly animal working under severe size constraints.