The ability to traverse along the surface of water is not shared by very many animals. There exists a few lizard species that can travel on water in order to catch insect prey, but it is the large-bodied arachnid known commonly as a fishing spider that demonstrates the most impressive talent for crawling on water. What makes fishing spiders unique compared to other water-walking animals is their ability to sink or remain buoyant at will. In fact, a fishing spider can survive for as long as a half an hour submerged beneath the water’s surface.
Numerous species of fishing spider exist, all of which have adapted to crawling on water, with the exception of one tree-dwelling species located in the southeast United States. These spiders are semi-aquatic and are the only arachnids that have adapted to walking on water. Another arthropod species commonly known as the water-strider is also able to traverse the surface of water, but these arthropods are technically insects, and they are considerably smaller in size than fishing spiders. Fishing spiders look similar to any other large and hairy land-dwelling spider species, but they possess hydrophobic hairs that allow them to remain buoyant at all times, no matter the speed at which they travel.
Fishing spiders dwell near streams and other small waterways in order to hunt and consume prey. These spiders catch prey by waiting to spot ripples in the water created by the movements of other flying insects as they make contact with the water’s surface. Once a fishing spider sees these ripples arrive at a stream’s bank, it lunges directly toward its prey without sinking. The water is a benefit in that it helps these spiders avoid predators, as a fishing spider can willingly descend beneath the water’s surface by encapsulating itself within an air-bubble. Most fishing spiders rely solely on insects for sustenance, but some species can grow large enough to consume tadpoles and even frogs.
Have you ever spotted a fishing spider or a water strider within a waterway?