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Elisa Areano


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How much do you know about the rays? We show you some basics about them. 

  1. Rays are fish, although they do not resemble friends with fins in your fishbowl at home, the rays belong to a group of Fish called Elasmobranch. 
  1. Around 200 different species of rays have been discovered in total. 
  1. The poison of the streaks was used as an anesthetic. Although painful, streak venom is usually not fatal unless the victims are stung in the chest or abdomen. In ancient Greece, the venom was extracted from striped thorns in order to be used as an anesthetic by dentists. 
  1. The jaws of the rays can crush the shells of the mollusks. Although the jaws of the rays are cartilaginous, you are strong enough to crush the clam shells and other mollusks. The calcified cartilage in its jaws has several layers of thickness, the softer nuclei of the elements of its jaws are supported by hollow and mineralized struts. This makes the jaws of the rays strong and light at the same time. 
  1. Some rays move like waves and others like birds. Most rays swim across the ocean waving their bodies in a wave-like motion. Others depress their sides up and down, giving them the appearance of a bird through their journey into the ocean. 
  1. Electric rays are named for their ability to generate and discharge electric currents strong enough to stun their prey or to defend the potential predators that can stalk you. 
  1. Rays can vary greatly in size. The smallest ray is the short-nosed electric ray that is approximately 10 cm wide and weighs about 400 g. 

The oceanic blanket is the largest ray that reaches up to 7m in wing length and weighs 2,000 kg.


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  1. Most shark species drown if they stop moving. White sharks, Mako sharks and salmon sharks (to name a few) do not have the muscles they need to pump water through their mouth and onto their gills. As they continue swimming, the water keeps moving on its gills, keeping them alive. 
  1. Sharks’ livers contain a lot of oil. This causes the liver to be a buoyant organ, which helps the sharks to keep the balance in the water. 
  1. Sharks do not follow the same routine of three meals a day as humans, they eat when they find food, no matter what time it is. 
  1. Surfers are more likely to die from drowning than by a shark attack, but it is true that big white sharks can be confused and feel intrigued by the way of a surfboard. Below the surface, a large white shark could confuse the outline of the board with that of a sea turtle, a seal, a walrus, or a sea lion. 
  1. Skeletons of Sharks are made entirely of cartilage, an elastic tissue that is much softer than the bones. When a shark dies, the salt from the ocean water completely dissolves its skeleton, leaving only the shark’s teeth behind. 
  1. The eyes of the sharks are on the sides of their heads, so they have an incredibly wide line of sight covering almost 360 degrees. Its panoramic view of the underwater world is inhibited only by two blind spots, one in front of the snout and the other directly behind the head. 
  1. Between 30% and 80% of the meat of a shark is made of water. A protein network gives the flesh its structure. 
  1. The size of a shark species are defined where they hunt: smaller sharks tend to feed near the bottom of the ocean, and larger sharks hunt in the middle depths and near the surface where they can more easily catch prey Bigger. 
  1. When hunting, the sharks stalk their victims, staying far enough away to remain hidden, but close enough to attack when the opportunity arises. 
  1. Big white sharks are fussy eaters. Their diet requires a lot of fat, and after a bite a big white shark can determine if the food will satisfy their nutritional needs. If not, the shark will leave the rest and swim away.


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With a slightly larger size than the Mako shark, Mako Prieto is an imposing shark with hydrodynamic features, its pectoral fins are long and have a slightly pointed and dark snout. 

Its habitat is still little known to researchers, although there are indications that it is epipelagic (describes of all marine species that live in oceanic areas between the surface and 200m deep). It is classified as viviparous aplacental because the offspring break the eggs inside the mother’s body and feed on the nutrients transmitted by it; before its birth, the offspring of the shark carry out the so-called intrauterine cannibalism or oophagy, which is only the action in which the most developed embryos in the mother’s womb feed on the eggs produced by the maternal ovary while these still are in gestation. 

The International Union for the Preservation of nature has classified Mako-Prieto shark as “Vulnerable” as a precautionary measure, partly because of many aspects that are still unknown to the species. 

Picture: Discovery Communications


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This shark receives its common name because of its bulbous head, small snout and a pair of small beards that it has on each side, very similar to the whiskers of a cat. On the dorsal part, this shark may have a gray or brown coloration depending on its maturity, while in the belly area the coloration is pale in all specimens. 

This species is predominantly demersal (it lives in the sandy and rocky bottoms) and is found at depths ranging between 1m and 75mm. 

The diet of the Cat sharks consists of small fish, mollusks (octopus, squid, clams), crustaceans, etc. 

Despite being a species of shark quite common in several places, scientific studies on this species are scarce, which has resulted in a “data deficient” classification by the International Union for the Preservation of nature. 

Picture: Andy Murch


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The silky shark acquires its common name because of the softness of its skin. Other notable features are a moderately long, pointed snout, large eyes, and a regular, non-prominent dorsal fin. It’s a kind of coastal, pelagic habits. As for their diet, this shark feeds mainly on Tuna, Mackerel, Las Lisas and Squid. 

Like other species of sharks, their reproduction is viviparous, which means that the embryos feed through the placenta. As for its classification, the International Union for the Preservation of nature has classified them as “almost threatened” which at the global level implies an indication of instability of the populations of this particular species. 

Picture: Alan C. Egan


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The great hammerhead shark differs from the other species of hammerhead sharks by having an almost straight head with a cleft in the middle and, that the first dorsal fin is very large, characteristic very particular of this species. 

It lives in the warm and tropical coastal regions of most of the world and feeds on fish, crustaceans and cephalopods from their specific regions. The great hammerhead shark is a viviparous species, a reproductive mode in which the embryos, through the placenta, are fed by the mother until the moment of birth. 

Remember that one of the most notable features of hammerhead sharks is to have a vision of 360 ° (peripheral), so the shark can see what happens in all around, taking advantage of this ability to hunt their prey.

Like the other species of hammerhead sharks, the International Union for the Preservation of Nature classifies the great hammerhead shark as “endangered”. 

Picture: Simon Rogerson


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Gulper shark is a species that inhabits the slopes of the continental coasts of different regions of the planet, being found from 50m to the 1440m of depth. Although it is true that it can inhabit from 50m deep sea, this shark is rarely seen at depths less than 200 m. 

Its most notable characteristics are very large and green eyes, a grey/brown coloration in the dorsal and clear part of the ventral area, and thorns in the dorsal fins. Also, your skin is covered with mucus. As for its diet, it feeds on: small bony fish, squid and crustaceans. Its type of reproduction is Ovoviviparous which means that the eggs are incubated inside the mother’s body, after that, the mother lays the eggs, and already outside the mother’s body the offspring are born. 

The Gulper shark is classified as “data deficient” by the International Union for the Preservation of nature and as for its preservation is considered a species vulnerable to the effects of the trawl fishery. 

Picture: Andy Murch


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The White saddled Catshark is characterized as a small-sized shark. As for its coloration it presents a pattern of dark and clear spots along its body as well as white dots. 

This shark is considered a kind of depth and inhabits the continental shelf at depths from 274m to the 457m. The type of reproduction is unknown, but the hypothesis is that they are oviparous. Because of the difficulty in accessing this specimen, abundance is also unknown, so the International Union for the preservation of nature cannot define its state of preservation. 

Picture: Andy Murch


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In hammerhead sharks, the head has a particular “T” shape, from the resemblance to a hammer, where the origin of its name comes from. For a long time the shape of his head has been the object of intrigue and study by the scientific community who have established different theories around this unique shark. 

With an excellent vision to recognize the depth, hammerhead sharks can see with great precision what happens to their surroundings, this being one of its greatest characteristics for the search of food. Their diet is mainly constituted of small fishes, crustaceans (like shrimps, lobsters, barnacles, etc.) and rays. 

Regularly, this species lives on the coasts and in the open sea. In addition, it is currently classified as: “Endangered” by the International Union for the Preservation of nature, hence the urgency to promote its preservation. 

Photo: Simon Rogerson


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This shark has been baptized as Tiger shark because of some similarities with the terrestrial animal. This species, on the dorsal part, has a dark blue-tinted gray coloring, and multiple streaks and dark spots along its body, similar to a tiger, although these characteristics tend to fade with age. In the ventral part it has a particular coloration between white and light yellow. 

The Tiger Shark lives in shallow waters, in bays and estuaries. Its diet is varied and consists of fish, birds, marine mammals, mollusks and crustaceans. Its reproduction is Ovoviviparous, type of reproduction in which the mother feeds the embryos, found in eggs, inside her body and then at the moment of birth are released from the body of the mother. 

The International Union for the Preservation of nature has classified the tiger shark as “almost threatened” which for this species is considered a low risk, but still as a latent risk. 

Picture: Alan C. Egan