There are many misconceptions about tarantulas, one of which is that they can survive underwater, allowing them to attack you by surprise for no reason. There are many reasons why that popular myth is false, and one of them is because tarantulas can’t breathe underwater.
Tarantula lungs cannot breathe underwater because their lungs don’t let them filter out water. Since they don’t actively breathe, they cannot hold their breath underwater. However, tarantulas and spiders can survive underwater for longer since their body hair traps some air that they can use to breathe.
In this article, we will explain why tarantulas can’t breathe underwater and highlight why it’s important not to put tarantulas into enclosures with deep water. While it can be tempting to create a paludarium enclosure for a tarantula to live inside, falling into the water could be fatal.
Why Can’t Tarantulas Breathe Underwater?
Tarantula lungs don’t let them breathe underwater. They have two sets of book lungs arranged in layers resembling pages. Gills are needed to absorb oxygen from water, and tarantulas do not have these.
Unlike mammals, tarantulas breathe passively, meaning they don’t actively pull air into their bodies. Air will passively enter the book lung openings and diffuse into their bodies. This means that tarantulas cannot hold their breath since they have no breathing control.
How do Tarantula Lungs Work?
Tarantulas have two sets of book lungs arranged into layers called lamellae, similar to book pages. Air passively enters the book lung openings and diffuses into their hemolymph, which acts like blood. Book lungs create more water loss than mammal lungs which is why they need high humidity to breathe.
Tarantula lungs are always moving air in and out at a specific rate. Since tarantulas breathe passively, they cannot hold their breath if they go underwater. However, tarantulas don’t need a lot of oxygen to function, and they’ve evolved a way to survive a fall into water.
Tarantula book lungs are positioned underneath their abdomen. This means if they swim or sit on top of the water, the lung entrances come into contact with it. Tarantula body hair can trap air around them, allowing them to continue breathing normally when submerged.
Can a Tarantula Hold its Breath Underwater?
Tarantulas do not actively breathe as humans do. This means they cannot hold their breath when underwater. Tarantula lungs passively move air in and out at all times, but Tarantula body hair can trap air, allowing them to breathe underwater.
Tarantulas have two sets of book lungs that passively move air in and out. The entrances to them are found underneath the tarantulas’ abdomen. If a tarantula is swimming or in a puddle, this could block the tarantula from breathing. However, tarantula body hairs trap air around the book lung entrances, allowing them to breathe underwater for a limited time.
Are there any Tarantulas that can Breathe Underwater?
There are no known tarantulas species that can get oxygen from water. They can breathe underwater if their body hair traps air around them. This would continue to give their book lungs access to fresh air for a limited time. A newly discovered species of tarantula has been documented doing this.
A “diving tarantula” was discovered in Australia, which lives in deep burrows and stays in them even when the burrow is completely submerged during the rainy season (https://www.australiangeographic.com.au/blogs/creatura-blog/2021/03/the-maningrida-diving-tarantula-sounds-like-a-bad-time/) They haven’t been given an official name yet since we know very little about them. These tarantulas can breathe underwater by coating themselves in a thin layer of air bubbles trapped by their body hair.
Are there any Spiders that can Breathe Underwater?
No spider has gills that allow them to live underwater permanently, but some spiders can spend extended periods underwater. Spiders can trap air around their body hairs which lets them continue to breathe underwater. While there are sea spiders, they are not true spiders, and they aren’t even arachnids.
There is only one known spider species that live entirely underwater. The diving bell spider (Argyroneta Aquatica) only goes to the surface to replenish its air supply. Scientists have discovered (https://www.adelaide.edu.au/news/news46181.html) that this species traps air in a dome-shaped web it creates between aquatic plants, which acts as a ‘gill’ for the spider. The diving bell they make can extract oxygen from the water, allowing them only to need to visit the surface once a day to supplement the air supply.
Tarantulas can trap air around their body hair, creating an air bubble so they can breathe underwater. Other true spider species can also do this and are very successful around water. The Dolomedes genus is formed of large spiders that are almost all semiaquatic. They usually hunt in water.
While there are hundreds of fishing spiders, the Dolomedes briangreenei (https://www.nationalgeographic.com/animals/article/160311-brian-spider-dolomedes-briangreenei) is an excellent example of a semiaquatic spider. They can walk on water, swim relatively well for a spider, and hide beneath the surface to avoid predators. Fishing spiders are sometimes kept as pets by invertebrate keepers.
Can Tarantulas Swim?
Tarantulas have a hydrophobic cuticle and hydrophobic body hairs, which means they will float on top of the water surface. However, they are not strong swimmers, and not all tarantulas can float very well. Heavier-bodied species will sink and drown.
Being hydrophobic allows the tarantula to swim, but it’s not their prefered movement method. The popular tarantula content creator Tarantula Collective has covered this topic in more detail (https://youtu.be/kIhan6_4v94?t=581). While tarantulas are not good at swimming, most can swim if needed.
Can a Tarantula Drown?
Tarantula body hair can trap air, allowing them to breathe in water. However, this is very limited, and tarantulas do need fresh air. A tarantula will drown if they are in the water for too long and cannot escape.
Most tarantulas will be fine if they fall into the water. They are hydrophobic, which allows them to float on the surface and paddle to shore. However, a sick or weak tarantula may struggle to reach land before running out of air. Heavier species are also more likely to sink in water, and as swimming is not common, they will be unable to make it to land.
Tarantulas cannot breathe underwater, but this doesn’t necessarily mean they will drown if they fall into the water. Their body hair is designed to trap air, allowing them to breathe for a short time when submerged in water. While tarantulas do not have gills, they can still breathe underwater for a limited time. Swimming isn’t natural to tarantulas, but most species will float on the surface, which allows them to paddle back to land.