Sea rays are flying-saucer-shaped fish with lengthy tails that skim alongside the seafloor. Many individuals lump all sea rays collectively and name them stingrays, however not all sea rays sting. In actual fact, some don’t even have stingers. A stingray is only one sort of sea ray. In total, there are some 600 species of sea ray!
Even with no stinger, rays might be harmful. We couldn’t anticipate any much less, contemplating they’re descendants of sharks. So, other than having very sturdy tooth, some rays can sting, and a few may even produce electrical discharges.
Sea rays are descendants of sharks
Sea rays are intently associated to sharks. Rays first appeared within the fossil report about 200 million years in the past, about 200 million years after the primary sharks. They’re believed to have advanced from flattened shark species.
Each animals share the identical common skeletal construction. However do you know neither sharks nor rays have bones? As an alternative they’ve cartilage, a light-weight, versatile and robust connective tissue. This distinctive adaptation improves their maneuverability and resistance underwater.
Thus, the ray is a cartilaginous fish belonging to the Batoidea superorder. These animals are straightforward to acknowledge as a result of they’re very flat and, within the overwhelming majority of instances, have lengthy, spherical fins to maneuver shortly by the water, and lengthy, skinny tails.
A really peculiar anatomy
These animals have fins that encompass their total physique. The pectoral fins type a large disc and start in the back of the cranium. These fins are at all times undulating as a result of, in the event that they didn’t, the animal would sink. The pelvic fins are fairly small and are built-in behind the pectoral fins.
The tail might be brief and sturdy or skinny and elongated. Nevertheless, most species have a reasonably lengthy and skinny tail.
As they’re fish, rays have gills to breathe. In actual fact, they’ve 5 pairs of gill slits within the decrease a part of their physique.
As well as, on the high of their physique, subsequent to the eyes, are the so-called spiracles, which are sometimes confused with the eyes. The spiracles assist them breathe when they’re half buried and camouflaged below the sand.
Watch out, some sea rays can sting
Many rays don’t also have a stinger, and those who have it use it as a defensive weapon. So these animals solely use it once they really feel attacked.
This stinger is positioned above the tail and is changed by one other infrequently. That’s why some rays have two or three stingers.
The stinger on some rays is toxic and very dangerous. Even a new child stingray already has poison in its stinger.
Electrical rays
Some rays additionally produce electrical shocks. Electrical rays spend a lot of the day camouflaged below the sand and exit to hunt at night time. They emit electrical shocks of as much as 220 volts to defend themselves in opposition to predators or to stun their prey.
We are all electric in a technique or one other, however these rays have enhanced this attribute with specialised organs. They produce their discharges from electric organs on both aspect of their head, the tail or close to the tail, relying on the kind of electrical ray. Moreover, they get to determine when to make use of them. They’ll generate a number of discharges in a row, however they lose energy.
Throughout the electrical organs are cells referred to as electrocytes organized in stacked columns. Electrocytes are modified cells both of muscle (most often) or neural origin. These cells generate the electrical punch. The variety of electrocytes in a column and the variety of columns dictate how a lot electrical energy the fish can produce.
Flotation system and feeding habits
The primary issue that gives buoyancy to sharks and rays is their giant liver (as much as 25% of the physique weight in some species).
Sharks and rays have tooth and can’t feed successfully with damaged or worn tooth. Fortuitously, they proceed to shed and change tooth all through their lives.
Sea rays are dynamic hunters. They use a intelligent approach. Due to their flattened form, they go to the underside of the ocean, transfer the sand with their fins to unfold it over themselves and conceal to catch their prey. Their favourite meals is crustaceans, mollusks and small fish.
And right here’s a curious truth. Since rays’ eyes are on the highest of the physique, however the mouth is on the underside, it may be tough for them to seek out their meals. Nevertheless, there’s quite a lot of life on the seabed, and any unsuspecting animal seems to be a superb possibility.
The ecosystem says thanks
Sea rays are invaluable to ecosystems. When these animals transfer throughout the seafloor and transfer sand, they assist construct microhabitats for tiny creatures. On this approach, they create houses for numerous small invertebrates. By doing this, additionally they assist many different marine species feed on small fish.
As well as, rays are oxygen mills. Some rays can dive to nearly 6,600 ft (2,000 meters) to feed. Once they return to the floor, they defecate, depositing important vitamins for phytoplankton. In case you didn’t know, phytoplankton produce half of Earth’s oxygen provide.
The elements mandatory for phytoplankton to hold out photosynthesis are carbon dioxide, mild and vitamins. The sunshine is obtained straight from the sun. And for the reason that ocean is an open system, it’s continuously exchanging carbon dioxide. However what in regards to the vitamins? Effectively, they float on the floor, however additionally they sink as a result of gravity to the underside of the ocean … And that is the place our saviors, the rays, are available.
An clever animal
Rays have a really giant mind in relation to their physique dimension. This superbrain is just not solely large however makes it fairly clever. In actual fact, rays acknowledge themselves within the mirror, a capability they share with dolphins, primates and elephants, indicating excessive cognitive features.
These extremely clever animals can create psychological maps of their underwater setting, an indication of their extremely developed long-term reminiscence.
Sorts of sea rays
Rays are categorised into 4 orders: Myliobatiformes (stingrays, manta rays, and eagle rays), Rajiformes (skates and guitarfish), Pristiformes (sawfish) and Torpediniformes (electrical rays).
Manta rays are fairly totally different from different sea rays, as a result of they’re a lot bigger, measuring as much as 26 ft (8 m). Moreover, the entrance of the physique of the manta ray is extra distinguished they usually have a much less round silhouette. Manta rays have their mouths within the entrance, whereas the opposite rays have their mouths below the physique.
Additionally, manta rays swim with their mouths extensive open, drawing in zooplankton and krill. So, they feed totally on planktonic organisms, however additionally they eat shrimp plus small and reasonably sized fish.
Right here’s a take a look at a number of of the 600 species of sea rays:
Habitat
Sea rays are discovered world wide. Some rays stay in recent water techniques. Most rays inhabit coastal waters near shore. Just a few species, like manta rays, stay in open oceans. There have even been instances of rays reaching rivers, though this isn’t frequent.
Backside line: Sea rays are descendants of sharks. They’ve sturdy tooth and a few might be harmful with stingers or electrical discharges.
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