Portia is a genus of jumping spider that feeds on other spiders (i.e., they are araneophagic or arachnophagic). They are remarkable for their intelligent hunting behaviour, which suggests that they are capable of learning and problem solving, traits normally attributed to much larger animals.

Intelligence

Portia often hunt in ways that seem intelligent. All members of Portia have instinctive hunting tactics for their most common prey, but can improvise by trial and error against unfamiliar prey or in unfamiliar situations, and then remember the new approach.

They are capable of trying out a behavior to obtain feedback regarding success or failure, and they can plan ahead (as it seems from their detouring behavior).

Portia species can make detours to find the best attack angle against dangerous prey, even when the 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.

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 likely has less than 100,000 neurons [!] (for comparison, a mouse brain has about 70 million neurons [!!] and a human brain has 86 billion [!!!]).

Portia can distinguish their own draglines from conspecifics’, recognizing self from others, and also discriminate between known and unknown spiders.

Social behavior

Members of the species Portia africana were observed living together and sharing prey.

If a mature Portia male meets a sub-mature female, he will try to cohabitate with her.

P. labiata females can discriminate between the draglines of familiar and unfamiliar individuals of the same species and between their own draglines and those of conspecifics. The ability to recognize individuals is a necessary prerequisite for social behavior.

smort spider