When you see a crab on your beach day, what is your initial reaction? Are you on the verge of being terrified and looking for cover? Are you immediately taken with this extraordinary animal that has made its way into our diet? It’s probably both! Crabs, in general, are fascinating marine creatures.
People around the world have enjoyed studying crabs’ behavior throughout history. Are you ready to learn everything about crabs that there is to know? The average crab lifespan, as well as the threats they face in the wild, are all covered in this article.
What Is Crab?
Crabs are decapod crustaceans that have a tiny extending ‘tail’ that is typically concealed entirely under their abdomens. They belong to the Brachyura infra order.
They live in all of the world’s oceans, freshwater habitats, and on Earth, and have a fixed number of pincers. They feature a solitary pair of pincers and a robust outer exoskeleton.
Certain crustaceans, such as king crabs and porcelain crabs, have acquired qualities that are comparable to true crabs via carcinization, despite having characteristics that are comparable. A crustacean grows from a non-crab-like form to a crab-like species via carcinization, which is a convergent evolutionary process.
Hermit crabs are thought to be the progenitors of king crabs. Squat lobsters, as well as hermit crabs, have been connected to porcelain crabs, which resemble crabs. Crabs have a mineral chitin-based outer skin and claws.
From the pea crab, which is 0.47 in (12mm) long, to the Japanese spider crab, which can reach a total length of up to 13 feet (3.96m), crabs come in a variety of sizes. All seas, as well as aquatic vegetation and land, including in tropical zones, are home to Little Crabs.
There are 850 different freshwater crab species. In order to prepare for molting, they lose their small old shell, which is weakened and eroded away. The primitive foundations of a new shell develop as the old shell is removed. In order to grow and break open the old shell’s molt at a vulnerable spot, a crab draws in a lot of water during molting.
When a crab breaks free from its previous exuvia shell and burrows, its new shell hardens. To make room for future growth, a crab head might stretch the soft new shell. Because of the crab’s legs’ mobility, they move sideways. Their legs give them more power during a sidelong stride.
Do investigate how long do hermit crabs live and how many legs crab have after learning about the lifespan of a crab.
The Rundown On Crabs
Decapods are crustaceans with ten limbs, as defined by the word. Decapods include crayfish, prawns, and shrimp.
The Jurassic epoch saw the first crabs come into existence. Crab diversity has reached almost 6,700 species. Crabs may be found in all oceans, freshwater, and on land, particularly in tropical areas. About 850 of all crab species are freshwater crabs.
Crabs are immediately recognized by their shell. On the outside of its body, this shell is a skeleton. Predators are thus shielded from them. Crabs have just a single pair of claws, along with their tough exoskeleton. Their most powerful weapon is their claws (pincers).
They fulfill at least three functions. The pincers’ task is to capture and control their victim while feeding. The pincers may exert pressure on a shellfish meal to shatter or unscrew the shell. Male battles also include pincers, which are used to communicate with other crabs.
The Crab’s Life Cycle
Crab species, such as Dungeness, can live up to 10 years. Infants and teenagers go through numerous cycles, and they don’t completely develop until they’re around 3 years old. The Dungeness crab’s life cycle is summarized as follows:
Five zoeal and one megalopa stage make up the larval phase, which lasts approximately 4 months. The crab appears to be little more than a blip floating around, attempting to grow strong, at this point. They are only around 1 millimeter long at this time and continue to molt as they grow larger.
The Dungeness crab starts to look like a real crab during the megalopa stage (post-larva), although it is tiny and attractive. These small guys stay close to the shore in the spring and summer to keep themselves safe from rough seas and predators. They’re just about half the size of a dime at this point.
The crab continues to grow in size and health while it molts, eventually reaching the juvenile stage of its life cycle. It will stay in this stage for two years. They may moult up to six times during this period! They spend the majority of their time in shallow waters, where they may feed and survive with relative ease.
Molting is the process of a bird’s feathers changing during its lifespan.
A crab’s old exoskeleton separates from the new one beneath it as it prepares to molt. The growing exoskeleton absorbs water at this time, growing larger. Their “molt line,” which runs across the carapace in the midline, becomes split as a result.
The flexibility to back out of its previous shell has been added to the new and incredibly soft crab. Crabs are very vulnerable to predators during this amazing accomplishment, so it is completed quickly.
While many are still found near land looking for food and mates, adult Dungeness crabs venture out into deeper waters, up to 2,000 feet. Guys and gals will discover each other at this point in the cycle, and the cycle will begin again!
How Long Do Crabs Live?
A crab’s average lifespan is three to five years. The species of the crab, on the other hand, has a big impact. The age of the various crab species varies as well.
Now, let’s look at the average life spans of several well-known crab species:
In the wild, king crab lifespan is around 20-30 years.
According to experts, snow crabs may live up to 20 years.
Blue Crab: Blue crabs may live for three to four years. They reach the age of 12 to 18 months. Growth rates are influenced by water temperature. In warmer water, they grow faster.
Dungeness Crab: Dungeness crabs have a lifespan of ten years.
As you can see, life expectancies vary greatly among these animals. The crab’s lifespan is also dependent on its environment. Crabs reared as pets may live longer than wild crabs if they are properly cared for.
Hermit crabs have been regarded as “throwaway pets” for a long time, with people expecting them to only last a few months. Nonetheless, if properly maintained, some species, such as the Coenobita clypeatus, may survive for up to 20 years.
How Long do Crabs Live Out of Water?
Like other aquatic species, blue crabs breathe through their gills. As long as its gills are kept damp, blue crabs can survive out of water for up to 24 hours.
To keep their gills from drying up and to hide from predators, crabs typically seek dark, cool, moist areas when they’re not in the water. The gills of crabs are also protected by movable plates.
The movable plates help to shut off their gills and keep them hydrated. Depending on the crab species, the amount of time a crab may spend out of water varies. While their gills must be kept moist, some crabs, such as coconut crabs and land hermit crabs, are land-based and may live without water.
The gills of these crabs are kept moist, and they may spend the rest of their lives out of the water. They would die if they were submerged in water.
Blue crabs, for example, are essentially amphibious and have developed to extract oxygen from an aquatic habitat. They can, however, survive for up to two days out of the water. The ability of the European green crab to live for a week without water has made it famous.
Factors That Affect the Crab Life Expectancy and Population
Nature makes predation a unavoidable reality! Crabs, like other tiny living creatures, have a number of predators they must keep an eye on throughout the day. Halibut, dogfish, sculpins, octopus, sea otters, and even other crab species are natural predators of the Dungeness crab.
Crab larvae are also consumed by salmon. Crab species are obviously more vulnerable while they’re still alive, and juveniles and babies prefer to stay towards the shore, where they can hide in vegetation and bury themselves beneath the sand.
Crabs can defend themselves from many predators thanks to their strong pincers and hard exoskeleton, which is fortunate news.
Human Behaviour We can’t help but eat a delicious crab. Overfishing of crab populations is the problem, resulting in harm. Overfishing does occur despite the fact that laws and restrictions are in place to try to prevent it.
Crabs are susceptible to the abuse of particular fishing equipment and boats, which is clearly utilized to capture them but may also harm ecosystems and cause poor water quality.
The environmental situation of the country. Climate change is probably the most significant threat to crab populations.
Climate change has a negative impact on a crab’s life, according to study, including “embryo development, spawning time and duration of the larval stages, the amount and spread of the settlement growth rates, size at maturity, and captureability.”
Exacerbation of low dissolved oxygen is exacerbated by sea level rise, which affects crab habitats. The higher the stress on aquatic life, the lower the concentration.
Crab species are also concerned about ocean acidification, or the erosion of seawater acidity caused by the absorption of carbon dioxide. This ocean acidity, in addition to stunting the growth of crabs, prevents them from forming new shells.
Humans can change two of the three factors by changing their behaviors, abiding by laws and regulations, increasing technology usage, and continuing research.
Different Types Of Crabs And Their Lifespans
The lifespan of each crab species varies greatly. External factors, such as if they are devoured by predators or captured by humans first, may influence the lifespan of these wild animals.
On average, a ghost crab lives three years. Before releasing their eggs into the water, where larvae develop, females transport them beneath their bodies.
The Portunidae population’s lifespan was estimated to be about one year, based on a unimodal size-frequency distribution. The Japanese spider crab is a big catch for any fisherman. It is the biggest crab, measuring 13 feet (4 meters) in leg span and weighing about 40 pounds (18 kilograms).
It may also live to be 100 years old, making it the longest-lived crab. Fiddler crabs may live up to a year and a half. Gecarcinidae are a family of true crabs that have adapted to live on land. Keepers have anecdotally reported that adult lifespans of at least 10 years have existed.
The little crab Lybia Edmondson belongs to the Xanthidae family and is native to the Hawaiian Islands. On average, these wild creatures live for five years. Nevertheless, crabs aged five to eight years were discovered in certain studies, indicating that a female blue crab lives for one to two years and a male lives for one to three years.
The Oldest of All The Crabs
Which of the oldest living fossils is a “crab,” as you may guess?
A horseshoe crab is visible! They have barely changed and evolved from what they originally were like, having been on this planet for almost 445 million years. A horseshoe crab, on the other hand, is not a genuine species crab…it’s just an interesting fact!
Hopefully, you gained something new and comprehended that the lives of creatures are reliant on human beings to maintain their lifespan constant. While crab will always be captured and served as a delicious dish, there are things we may do to assist their habitats and livelihoods.
Are you interested in purchasing live Dungeness crab for your next sustainable meal? Fathom Seafood has a wide variety of products to choose from.