Setting up the right tank setup is vital for the survival of pet hermit crabs, as there are significant differences between the breathing abilities of marine and land hermit crabs.
Land hermit crabs can’t remain underwater for 20-30 minutes. Terrestrial hermit crabs need small amounts of water to store and keep their gills wet, enabling them to breathe.
Owners must provide optimal conditions to prevent hermit crabs from drowning, including ramps, small pools of water, and accessories that enable them to escape the water if they get stuck.
Can My Hermit Crab Drown?
Marine and land hermit crabs have entirely different living requirements. Terrestrial hermit crabs are more commonly kept as pets but are most at risk of accidentally drowning.
Marine Hermit Crabs
Marine hermit crabs can’t drown but need the right temperature and salinity to survive. Without them, they won’t thrive and may die soon after arrival.
Aquatic hermit crabs have large, prominent gills near their front walking legs. They breathe by absorbing oxygen from saltwater and transferring it to their gills. Oxygen then reacts with a hermit crab’s blood, where they release carbon dioxide through the mouth in the form of tiny bubbles.
Aquatic hermit crabs spend most of their time in the water; the wetter their gills, the more oxygen they breathe. As the Journal of Experimental Marine Biology and Ecology describes, exposure to saltwater changes the breathing rate because the oxygen reacts to the water in the gills.
Land Hermit Crabs
Land hermit crabs can’t breathe underwater and can drown because their gills aren’t sufficiently developed for prolonged water exposure.
While hermit crabs need to dampen their gills to breathe, they can’t be submerged for too long. They need various escape routes to get out of the water when necessary.
According to Comparative Biochemistry and Physiology, hermit crabs experience breathing difficulties when exposed to the wrong environments.
Land hermit crabs need to remain predominantly dry. However, owners must be careful because they can suffocate if their gills are permitted to dry out gradually.
Do Land Hermit Crabs Have Gills?
All hermit crabs have gills, but they need access to water to breathe.
According to Smithsonian’s National Zoo & Conservation Biology Institute, land hermit crabs have much smaller gills than their marine cousins, which is why they can’t spend much time underwater.
A land marine hermit crab’s gills are located in the brachial chamber. Their moist gill chambers have several blood vessels that enable gas exchange.
The chamber and gills act like lungs, allowing hermit crabs to breathe through the air instead of the water. However, to breathe, they must obtain oxygen from humid air.
Hermit crabs have a unique physiology, enabling them to store and retain water in their shells, which they obtain from the ground or in shallow pools.
As mentioned, terrestrial hermit crabs can’t breathe underwater. They spend about 95% of their lives living on dry land, periodically entering the water for around 20 minutes at a time to:
- Dampen their gills
- Store water in their shells
Doing so prevents suffocation and enables land hermit crabs to thrive in captivity.
How Long Does It Take for a Hermit Crab To Drown?
Marine hermit crabs can breathe underwater for as long as necessary. There’s a risk of other environmental factors posing a threat to their lives, such as temperatures and low salinity levels.
Land hermit crabs can only breathe underwater for around 20-30 minutes. Juvenile or sick hermit crabs may only last 10 minutes underwater before they succumb to suffocation.
Nobody knows exactly how long hermit crabs can survive underwater. Hermit crabs have an innate sense of how long they can survive and will attempt to get out of the water before they perish.
Caring for land hermit crabs isn’t always easy because they need access to water, so you’ll need to introduce preventative measures to stop them from drowning.
How To Prevent Hermit Crabs From Drowning
It may surprise you that hermit crabs can’t swim, so they need additional assistance escaping water to prevent drowning.
You can assist by adding the following features to a hermit crab’s enclosure:
Ramps are the best way to prevent hermit crabs from drowning because they provide an easy exit from the water. You can get plastic mesh ramps from most aquatic stores that hermit crabs can grip onto.
Plastic canvas ramps are another good option, as they don’t rust. Monitor the ramps to ensure your hermit crabs can walk up and down whenever necessary.
Hermit crabs need external water sources in their enclosure, including two pools of water.
One pool should contain dechlorinated freshwater, while the other needs a sprinkling of marine salt. Never use table salt because iodine is toxic.
When searching for pools, show a preference for options with a simple design. While pools with different levels may be tempting, they’ll confuse hermit crabs, increasing the risk of drowning.
Don’t make any pools too deep because hermit crabs may be unable to escape and could drown.
The water should be deep enough for hermit crabs to submerge themselves and their shells underwater but shallow enough not to confuse their exit plan.
Hermit crabs aren’t very large, so you don’t need to fill the pools excessively.
Land hermit crabs require the right amount of humidity to breathe. Most owners follow the 80/80 rule when setting up tanks, which involves the following:
- The humidity level should be 80%
- The temperature should be 80 degrees
This humidity introduces moisture to the air, enabling hermit crabs to breathe.
You can use a hygrometer to measure humidity and a misting spray to apply more humidity to the tank. It’s advisable to closely mirror the natural environment of hermit crabs to keep them healthy.
Unfortunately, owners can lose hermit crabs due to drowning if the setup is wrong. So, ensure the tank setup is suitable (shallow water, easy exit points via ramps, etc.) to minimize the drowning risk.