best detour takes a Portia out of visual contact with the prey, and sometimes the planned route leads to abseiling down a silk thread and biting the prey from behind. Such detours may take up to an hour, and a Portia usually picks the best route even if it needs to walk past an incorrect route. If a Portia makes a mistake while hunting another spider, it may itself be killed. Nonetheless, they seem to be relatively slow thinkers, as is to be expected since they solve tactical problems by using brains vastly smaller than those of mammalian predators. Portia has a brain significantly smaller than the size of the head of a pin, and it has only about 600,000 neurons. Portia can distinguish their own draglines from conspecifics, recognizing self from others, and also discriminate between known and unknown spiders. Hunting techniques Their favorite prey appears to be web-building spiders between 10% and 200% of their own size. Portia looks like leaf detritus caught in a web, and this is often enough to fool web-building spiders, which have poor eyesight. When stalking web-building spiders, Portia try to make different patterns of vibrations in the web that aggressively mimic the struggle of a trapped insect or the courtship signals of a male spider, repeating any pattern that induces the intended prey to move towards the Portia. Portia fimbriata has been observed to perform vibratory behavior for three days until the victim decided to investigate. They time invasions of webs to coincide with light breezes that blur the vibrations that their approach causes in the target's web; and they back off if the intended victim responds belligerently. Other jumping spiders take detours, but Portia is unusual in its readiness to use long detours that break visual contact. Laboratory studies show that Portia learns very quickly how to overcome web-building spiders that neither it nor its ancestors would have met in the wild. Portia's accurate visual recognition of potential prey is an important part of its hunting tactics. For example, in one part of the Philippines, local Portia spiders attack from the rear against the very dangerous spitting spiders, which themselves hunt jumping spiders. This appears to be an instinctive behavior, as laboratory-reared Portia of this species do this the first time they encounter a spitting spider. On the other hand, they will use a head-on approach against spitting spiders that are