Portia jumping spiders use deceptive web vibrations and planned detours to hunt other spiders despite pinhead-sized brains, University of Canterbury researchers reported in a peer-reviewed review.
The 2020 review in Frontiers in Psychology, led by comparative-cognition researcher Fiona R. Cross, found evidence of flexible problem-solving, internal representation and prey-specific hunting tactics in the genus Portia.
When invading another spider’s web, Portia moves silk with its eight legs and two palps to produce vibration and tension patterns, according to the review.
Some signals mimic an insect trapped in the web, drawing the resident spider within striking distance.
The researchers said Portia tests different signals when prey fails to respond and repeats patterns that produce the desired reaction.
🕷️ A jumping spider climbs a woman's jeans and appears to respond to her hand gestures by leaping toward a plate of food to successfully catch a fly, showcasing these spiders' exceptional vision and hunting agility. pic.twitter.com/iySxGi8bEN
— Bella (@stockbella) August 10, 2026This trial-and-error method allows the predator to adjust its approach to different spiders, including species capable of killing it.
A 2016 experiment by Cross and Robert R. Jackson tested 15 spider-eating jumping-spider species from six countries.
Read: Zelensky Details Operation Spider’s Web
Each species selected a walkway leading to previously visible prey significantly more often than the incorrect route, even after researchers removed the visual cue.
The experiment used spiders with no prior experience of the apparatus. The authors said the results supported planned route selection based on an internal representation rather than a simple stimulus-response sequence.
The 2020 review concluded that Portia’s abilities fit a continuum of intelligence defined by flexible problem-solving.
Its authors cautioned that the evidence concerns specialised cognition and does not make the spiders equivalent to vertebrates across all cognitive tasks.
