Gigantic fishing spider is one of nature's best scuba divers

Dolomedes spiders, also known as fishing spiders, dock spiders, and "cottage monsters" are unique predators with amazing hunting abilities. They wait by the edge of a lake, pond, or river to ambush small fish that come to the surface. The spiders can detect ripples and then quickly run across the surface of the water. They use their forelimbs that are equipped with claws to hook their prey and inject their prey with venom with their hollow jaws.
Fishing spiders are also capable of climbing beneath the surface of the water. The hairs on their bodies trap air bubbles that encase the spiders as they hunt underwater. Because they breath through openings in their abdomens, they can use the trapped air to breathe and stay submerged longer.
The fishing spider hunts for mayflies and other insects on the surface of the water, using the water as a web. They can detect ripples and vibrations which indicate where their prey are located. The spider can estimate distance and direction, as well as discern the vibrations given off by predators such as trout. Powerful predators, they are capable of eating fish as large as a small goldfish. They will prey on tadpoles as well.
These spiders are similar in appearance to wolf spiders and are often confused with them. They differ in their markings, their eyes, and the fact that wolf spiders carry their young on their backs. Although frighteningly large, they rarely bite people and they help keep the insect population in check. Seeing them around the cottage is actually a good thing for people who don't want to be bitten by horseflies or mosquitos.