What do skates and rays have in common

Can a manta ray kill you? Manta Rays are not dangerous. They are even harmless and can't hurt any diver or swimmer. They are usually very curious and swim around the divers. They can sometimes even jump out of the water to get rid off their parasites!

Do stingrays lay eggs? They are one of two recognized species in the family Potamotrygonidae the other being the Long-tailed River Stingray. The species does not lay eggs. Stingrays are ovoviviparous: bearing live young in litters of five to The female holds the embryos in the womb without a placenta. Can you eat Stingray? Yes, you can eat stingray.

Stingrays are popular to eat in countries such as Malaysia and Singapore, and seen as a delicacy in many areas. They're commonly cooked over charcoal with spicy "sambal" sauce or soy sauce. How many people die a year from stingrays? Fatal stingray attacks on humans are exceedingly rare. From their flapping wings to their long tails to the way they seem to fly through the water, rays are some of the most compelling sea animals for humans to watch.

However, it may be difficult for casual viewers to determine if the animal they see is truly a stingray or perhaps its visually similar cousin, the skate. While the sea creatures have a lot of common features, important differences help distinguish between the two animals. Skate and stingray animals belong to the same family — elasmobranchs — because they have cartilage skeletons and gill slits near their heads. However, rays are larger with stinging spines on their tails while skates are small with prominent dorsal fins.

Rays give birth to live young viviparous , and skates lay eggs oviparous. The reason stingray and skate animals are difficult to distinguish is because they are so closely related. In fact, both species are elasmobranchs; this group, which also includes sharks, shares two common features — a skeleton made of flexible cartilage, rather than bone, and gill slits near the head.

These elasmobranchs are called oviparous or egg-laying. The young of both oviparous and viviparous forms hatch, or are born, as fully developed, miniature copies of their parents that are capable of actively avoiding predators, unlike the larval stages of many teleost fishes.

The relatively large size reached by all elasmobranchs prior to hatching, or birth, also ensures that they are capable of consuming a wider variety of potential prey. All skates exhibit the most primitive form of oviparity, termed extended oviparity. Extended oviparity is a mode of egg-laying where embryonic development occurs primarily outside of the mother, and can last for very long periods of time.

More specifically, the energy-rich ova are fertilized within the oviducts; quickly encapsulated in keratinoid egg cases secreted by the shell or nidamental glands; and then deposited on the substrate sequentially in pairs of two. Once the egg cases are deposited on the bottom termed oviposition , the embryos receive no further parental care, and are nourished solely from yolk stored in the yolk sac.

The tough egg case provides an osmotically independent environment until the embryo is capable of urea retention and osmoregulation. It also forms the only protective barrier against predators and the outside environment that the embryo has.

Development within the egg case is a slow process that can last for a period of up to 15 months, after which the embryo or miniature skate pushes its way out of the capsule. Oviparity is thought to be the more primitive or ancestral condition in elasmobranchs. A gradual evolutionary shift from oviparity to viviparity in some species may have served to better shield young against potential predators and other hazards, as well as to offer a more uniform developmental environment.

The young of oviparous elasmobranchs also tend to be smaller than those of viviparous elasmobranchs because the amount of nutrients available to the developing embryo is limited to what is stored in the yolk sac.

Larger young, in turn, are better able to avoid predators, perhaps explaining an overall evolutionary shift away from oviparity, especially in more pelagic species. Although oviparous species provide no parental care in the form of nutrients after the egg is deposited, little is known about "parental care" in oviparous elasmobranchs.

None are known to actively guard their eggs or build nests, but it is possibel that egg-laying elasmobranchs select appropriate substrate for their eggs so as to maximize the chances of survival of the developing embryos. The females of at least one species of bullhead shark family Heterodontidae are known to pick up their eggs in their mouths and then wedge them into rocks and marine vegetation.

Northwest Atlantic skates in a holding tank at BIO. Skates are oviparous, laying tough egg cases also called "mermaids purses" on the seafloor from which miniature skates hatch. A newly hatched thorny skate Amblyraja radiata. Note the swelling of the body cavity, indicating the presence of an internal yolk sac. The egg capsule of a thorny skate Amblyraja radiata , with one wall cut away to reveal a developing embryo.

Mating behaviour has been observed in the wild in very few species of elasmobranch. Only five of the more than species of batoids have been observed copulating in the wild, leaving most aspects of their natural sexual behaviour unknown.

Female receptivity to copulation likely depends on hormonal status. For example, the process of parturition might produce some form of sexual pheromone or olfactory attractant for male rays. Precopulatory mating behaviour i.

For example, male eagle rays Aetobatis narinari dive upon and gouge the back of females during courtship, and the copulatory bites of the male roughtail stingray Dasyatis centroura , round stingray Urolophus halleri and the bullseye stingray Urolophus concentricus - among others - can inflict lasting scars on the female. Mating and insemination is often a long, drawn-out process, especially in batoids, where copulation can last for several hours.

In some species of elasmobranch, sperm are then stored in the nidamental gland of the female, in some cases for months or longer, before they are released to fertilize ovulated ova.

A barndoor skate Dipturus laevis captured aboard a commercial longline vessel. Many species of skates are rays are becoming increasingly important in fisheries around the world. Skates, for example, have edible "wings", the flesh of which is firm, white, sweet and similar in texture and taste to that of scallops. The subclass Elasmobranchii includes sharks, rays, and skates. Elasmobranchs are characterized by cylindrical or flattened bodies, five to seven pairs of gill slits, an upper jaw not fused to the cranium, and placoid scales.

Placoid scales, also referred to as dermal denticles, have the same structure as a tooth consisting of three layers. These scales are arranged in a regular pattern on sharks and irregular patterns on rays and skates. Is it easy to distinguish rays and skates from sharks? The primary characteristic of dorso-ventrally flattened bodies makes rays and skates easy to distinguish from sharks.

Where in the world do rays and skates live? Rays and skates live in oceans throughout the world. Most rays and skates are benthic while some are pelagic. Some rays also live in freshwater habitats.

In Florida, the Atlantic stingray Dasyatis sabina is known to live in freshwater along the St. Johns River waterway as well as inland freshwater lakes. These populations of the Atlantic stingray are unique in that they spend their entire life cycle in freshwater.

Are stingrays dangerous to humans? Stingrays have venomous spines along or near the base of the tail. The muscular whip-like tail can be lashed about quickly in defense. Occasionally beach-goers will accidentally step on stingrays that are partially buried in the sand near the beach resulting in a painful, serious wound in the foot. Although the spines are dosed with venom, wounds are not normally lethal. However, it is still important to get medical attention as soon as possible to avoid any potential infection.