Discover the Only Spider That Lives Underwater and Can Swim

Did you know that, as of right now, there is only one spider that lives almost the entirety of its life underwater? That’s right, this underwater spider is an aquatic species and is even able to swim effectively. But do you know what species this is?

If not, don’t worry! Below, you’ll find out just which spider decided to trade webs for waders, as well as additional information about this fascinating species. Ready to learn more? Let’s dive right in. 

What Spider Lives Underwater?

The planet’s waters are filled with various interesting and mysterious species that seem like something straight out of a fictional book. A spider that lives almost entirely underwater is one of these amazing animals. However, what spider is this?

If you want to learn more about underwater spiders, look no further than the diving bell spider. 

About the Diving Bell Spider

The diving bell spider (Argyroneta aquatica), also known as the water spider, is the only aquatic species of spider in the entire world. Although it may seem like they’ve traded the ways of their terrestrial cousins for a life under the sea, diving bell spiders are actually quite similar to the spiders you see around your home. They still use webs to hunt for their prey and are just as important to the ecosystem.

Appearance

Outside of their preferred habitat, one of the biggest differences between diving bell spiders and terrestrial spiders is size. See, spiders are one example of animals that display sexual dimorphism. This means that males and females of a species look different. For spiders, this often presents in size.

Typically, female spiders are larger than male spiders. However, this isn’t the case for diving bell spiders. For this unique species, male diving bell spiders are larger than female diving bell spiders. Many scientists attribute this to the fact that males have a more active and hands-on style of hunting than females, which requires better swimming abilities.  

Both males and females of these underwater spider species have a dark brown appearance. They have fine hairs on their underside that often make them appear made out of velvet. Many times, it is thought that the underside of the diving bell spider is silver. This is because as they break the surface of the water and are re-submerged, they carry an air bubble with them. This air bubble reflects and refracts light in order to create the illusion of a white or silver appearance. 

Habitat

The diving bell spider is native to Europe and Asia. Here, it is found only in freshwater ecosystems. Because of how they construct their webs, they prefer areas where submerged vegetation is available. This can include a variety of water sources, such as lakes, ponds, canals, marshes, and streams. They are uncommon in rivers unless they are slow-moving. 

In most of their region, only a single species exists. However, Japan has its own subspecies to claim: A. a. japonica.

Diet

The underwater spider has a diet not too unlike its terrestrial cousins. Most of their diet comprises aquatic insects and their larvae that coexist in the same waters as the diving bell spider. However, they also have some unique prey. This includes crustaceans that terrestrial spiders may otherwise not be able to access. 

The diving bell spider is preyed on by larger aquatic or semiaquatic animals, such as fish, and amphibians, such as frogs. 

Diving Bell Spiders and Aquatic Behavior

Although the diving bell spider is the only underwater spider, it’s not the only species of spider that likes water. Other species are known to live around water and even dive occasionally, with some types of semi-aquatic spiders diving for several hours at a time. 

The diving bell spider is unique because they spend almost all of their lives underwater. Other than coming up briefly for oxygen (that’s right, they still breathe air like other spiders!) and occasionally bringing their prey to the surface, the entire life of the diving bell spider is present underwater. This includes hunting, mating, and nesting. Typically, the diving bell spider will only come to the surface once per day for oxygen.  

In order to build a nest underwater, the diving bell spider exhibits some interesting aquatic behavior. First, the underwater spider will string its silk between submerged plants. Then, the spider will go to and from the surface, bringing down air bubbles to “inflate” their web. This allows them to catch prey passively. 

The photo featured at the top of this post is © RajatHegde/Shutterstock.com