Crayfish, like every other animal species on the planet, breathe oxygen. But how do they obtain oxygen? And do they need water to breathe? Let’s get into it!
Because crayfish are aquatic, they have the same respiratory system as fish, crabs, and lobsters that breathe oxygen via their gills. Like crabs, their gills have adapted to extract oxygen from the air as well as water, but they need to be moist to do so.
Gills, the respiratory organ of crayfish, work in a manner similar to our lungs. Small molecules of oxygen are drawn into the bloodstream when they travel over the surface of the gills or lungs. The main distinction is that gills draw oxygen from water rather than air.
The gills of crustaceans, like crayfish, lobsters, and crabs) are located in the thoracic chamber (chest cavity) and attached to their front legs. They resemble feathery patches at the ends of legs or at the junction of legs and body shells.
The feathered effect is caused by the structure of the gills, which need as much surface area as possible to get the maximum oxygen from the water passing over them.
Do Crayfish Breathe Underwater?
Yes, the gills of crayfish are mainly adapted to allow them to breathe underwater. They can stay underwater for as long as they like. They will survive as long as the water is oxygenated.
Crayfish (aka crawdads or crawfish) like other big crustaceans, utilize their gills to collect oxygen from the water.
This creature’s gills, which are located on both sides of the body and at the base of each leg, function in the same way as those of most aquatic organisms, drawing oxygen into the circulation when water flows past them.
However, since crayfish gills are sensitive enough to draw moisture from the air, as long as the water is maintained wet and the crayfish remains in humid locations, the crayfish will be able to travel freely on land.
As a member of the crustacean family, the respiratory anatomy of the crayfish is very much a similar design to that of lobsters and crabs and like these fellow crustaceans, the crayfish must breathe totally via its gills.
These gills, which may be recognized by their fuzzy grey or brown appearance, can be seen on the crayfish’s sides and at the base of appendages.
Crustacean gills absorb oxygen into the circulation as water runs through them, however, these gills can do so much more.
Do crayfish need to come up for air?
No, they do not have to come up for air unless the water is exceptionally low in oxygen.
If a crayfish is to be kept in a tank of water and there is no way for the crayfish to climb out of the water, there must be oxygenation of the water otherwise if all oxygen becomes depleted in the water, the crayfish will not be able to obtain the oxygen it needs from the stagnant water and will basically drown.
Crayfish gills are an incredibly sensitive organ; as long as the gills are wet, they may pull oxygen into the body from moisture in the surrounding environment.
As a result, the crayfish can walk on land and can traverse incredible distances in the appropriate conditions provided there is enough humidity.
Surprisingly, a kind of crayfish called a “terrestrial (land-dwelling) crayfish” may be found in certain parts of the midwestern United States.
They are able to stay on land for extended periods of time because of this crayfish’s unique gills, which enable them to spend most of their lives in terrain with high water tables, albeit not constantly submerged. They can, however, only survive in freshwater or brackish waters.
These burrowing crayfish can survive even hundreds of miles away from a lake, stream, or river because they dig into mud and damp earth, which provides sufficient moisture to keep their bodies moist enough for their gills to function.
Can crayfish breathe air?
Crayfish, like other big crustaceans, acquire oxygen via their gills. However, since crayfish gills are sensitive enough to draw oxygen from the air, the crayfish may travel freely on land as long as their gills are maintained wet.
Crayfish, like fish, breathe via internal gills, although many (particularly burrowing crayfish) can stay out of water for extended periods of time under humid circumstances. The plume-like gills are found in gill chambers on both sides of the body.
This is somewhat similar to most crabs, but there are also crab species able to live entirely on dry land such as the coconut crab. On the contrary, lobsters are more sensitive to oxygen levels and lobsters cannot live for extended periods on land.
Can crayfish live on land?
Due to their lack of a direct relationship to bodies of water, land-lobsters are also known as Terrestrial Crayfish. These crayfish, like their aquatic siblings, utilize gills to take oxygen from water.
Burrowing crayfish or Red Swamp Crayfish, unlike their water-soaked crayfish, spend most of their life on land.
As they burrow the earth, the crayfish fling soft mud up around their exit holes. If you look carefully, you may see scratches and grooves in the new mud formed by its chelae (claws).
These chimney-like structures may ultimately reach heights of 3 to 8 inches above the earth’s surface.
These omnivorous crayfish emerge from their burrows at night in quest of live and dead plant and animal food. If you use a flashlight and use stealth, you may be able to locate them several feet from their underground homes.
Despite their sometimes-annoying reputation, burrowing crayfish have been demonstrated in studies to be crucial components of some terrestrial ecosystems. Their burrows aid in drainage by allowing water to flow directly into the earth.
Their foraging aids in the recycling of nutrients. They transport oxygen and nutrients deeper into the soil profile.
Crayfish burrows that have been abandoned offer homes or protective shelter for a variety of different invertebrates as well as a few vertebrates.
How long can a crayfish live out of water?
Crayfish can, in theory, survive their whole life on land as long as they are kept in a humid enough environment e.g. with frequent rainfall or mud.
They do need to be extra careful when out of the water though, as not only fish but also land-dwelling animals love to eat crayfish!
As long as the crawfish’s gills are kept wet, any type of crayfish may live for many days outside of water thanks to its modified gills, which let it breathe air and not just water.
Sum up: do crayfish breathe air or water?
Crayfish have gills for breathing underwater but can also breathe air. When in water the gills work in much the same way that gills normally work in other water creatures like fish.
The difference is that crayfish have such sensitive gills that provided the gills are kept moist they can suck in oxygen from moisture in the air. This is the same for most crabs, but lobsters do worse on land.
This ability to breathe air when on land allows the crayfish to migrate from one body of water to another and accounts for the territorial expansion of the crayfish. And although crayfish are strictly freshwater animals, some can actually tolerate brackish saltwater.
The gills used by crayfish are analogous to those of octopi, squids, crabs, and lobsters, which I have also written about, so check out those posts if you’re interested!