Dock spiders are a fascinating arachnid species. While many find their massive size (female dock spiders can grow to be as large as an adult’s hand), and chilling appearance terrifying, they are one of the few animals in the world capable of walking on water. The ‘secret’ is their widely-spaced legs and water-repelling hairs.
Dock spiders are Canada’s largest native spiders. They are also called wharf spiders or fishing spiders. There are 5 varieties of dock spiders which reside near rivers, streams, ponds, marshes and reservoirs. Favoured habitats include shorelines with dense plants or man-made structures (like boat houses), and within forests, under rocks, logs and in tall plants.
Dock spiders are not common household pests. They can however find their way into homes, boathouse, boats and even swimming pools located near their preferred habitats.
Dock spiders have 2 rows of eyes, brownish-grey colouring, and have black and brown markings on their abdomens. Their 8 legs are striped, widely spaced and have water-repelling hairs on them. Their body size varies between male and female spiders. The body of a female dock spider ranges from 15 to 26 millimeters in length, while males are typically half the size, averaging between 8 and 13 millimeters in length. Dock Spiders are often mistaken for wolf spiders and vice versa. The wolf spider, by comparison, is smaller and has three rows of eyes.
Dock spiders feed on minnows, frogs, tadpoles and water insects. They hunt for food by dangling over water and resting their front legs on the water’s surface to feel for vibrations. Once nearby prey is detected, they literally run across the water’s surface to attack it and inject their venom. Another amazing fact is that they can consume prey as large as almost 5x times their own size.
Female dock spiders can produce egg sacs containing up to 1,000 spiderlings, which they carry beneath their body. Dock Spiders have been referred to as “nursery-web spiders” because they build nests with their webbing for their hatched spiderlings within tall grasses, under docks or between rocks. These nests provide shelter and protection while the immature spiders shed their exoskeletons and develop into mature adult spiders.
Dock spiders will deliver a bee-sting level bite to humans if they feel threatened or are startled. Situations that have ended in dock spider bites include when the spiders were held, sat on, stepped on, or were trapped inside clothing that was put on.
Dock spiders cause more fear due to their enormous size and their ferocious appearance. They do not cause damage to property or harm people.
We advise against attempting to remove dock spiders or detach an egg sac from a spider by hand. This significantly increases the changes that you are bitten. Attempting to use chemical and sprays around or on water to eliminate dock spiders is also advised against as this poses a serious safety risk to you and the environment.
Signs of dock spider include the remains of large exoskeletons and tent-like nursery webs in and around plants or even attached to manmade structures. Tips for helping to keep dock spiders away from your home include the following:
Remove piles of rock or wood debris around your home, sheds or boathouses to eliminate possible locations for shelters.
Keep all shoreline plants trimmed to eliminate nesting sites and possible hideouts.
Remove or minimizing any standing water on your property where possible.
If you think you are infested with dock spiders, or have an uncontrollable, intolerable infestation, reach out to a licensed pest control company. They have the expertise to help you safely control and treat a dock spider infestation.
Call 1 (800) 263-5055
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