Invertebrates
Fishing Spider
Dolomedes spp. · also called dock spider, raft spider
At the edge of a still pond, a fishing spider rests motionless on the water’s surface, front legs spread to feel for the faintest ripple, ready to dive beneath the surface in an instant if the wrong kind of vibration arrives first.
Overview
The fishing spider, genus Dolomedes, is a large, semi-aquatic spider found near ponds, streams, and lake margins across much of the world. Its ability to walk on water, dive to escape danger, and hunt by reading surface vibrations sets it apart from nearly every other land-dwelling spider.
A hunter that treats water as solid ground
Where most spiders avoid water entirely, the fishing spider has turned the water’s surface into its primary hunting platform, walking, diving, and striking across a medium that would trap or drown almost any other spider its size.
Status
Least Concern — widespread and common across suitable wetland and shoreline habitat throughout much of the world.
Fishing Spider: common questions
Can fishing spiders really breathe underwater?
A fishing spider cannot breathe water directly, but it can trap a thin layer of air among the dense hairs covering its body, allowing it to remain submerged for a period of time when diving to escape a predator or pursue prey before it needs to return to the surface for fresh air.
How does a fishing spider walk on water without sinking?
A fishing spider's legs are covered in fine, water-repellent hairs that exploit surface tension, distributing the spider's weight across the water's surface film in much the same way a water strider manages to stay afloat, allowing the spider to walk and even run across still or slow-moving water.
Are fishing spiders dangerous to people?
No, despite their large size, fishing spiders are not aggressive toward people and possess only mild venom intended for subduing small prey, meaning a bite, while uncomfortable if it happens, poses no serious danger to a healthy adult.
How does a fishing spider find its prey?
A fishing spider senses prey largely through vibrations transmitted across the water's surface, detecting the ripples produced by a struggling insect or small fish before moving in to strike, a hunting method that relies on touch and vibration rather than primarily on sight.