Australian Navy diver de Gelder is spending Shark Week getting up close and personal with great whites. Cavalli has not yet responded to a request for comment from DailyMail. The viral video of the alleged shark attack begins by showing Cavalli in good spirits as. After a man was attacked while spearfishing in Hawaii and a kayaker bitten in California, we take a look at other notable shark attacks in recent memory. A pair of surfers have narrowly escaped a savage shark attack on a seal just feet away from them. Nauset Beach in Orleans, Massachusetts closed on Monday after the. Directed by David Worth. With Thorsten Kaye, Nikita Ager, Dan Metcalfe, Caroline Bruins. The mutant sharks from Dr. Cravens experiments in Shark Attack 1 are back. Shark Wikipedia. Sharks are a group of elasmobranchfish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade. Selachimorpha or Selachii and are the sister group to the rays. However, the term shark has also been used for extinct members of the subclass Elasmobranchii outside the Selachimorpha, such as Cladoselache and Xenacanthus, as well as other Chondrichthyes such as the holocephalideugenedontidans. Under this broader definition, the earliest known sharks date back to more than 4. Acanthodians are often referred to as spiny sharks though they are not part of Chondrichthyes proper, they are a paraphyletic assemblage leading to cartilaginous fish as a whole. Since then, sharks have diversified into over 5. They range in size from the small dwarf lanternshark Etmopterus perryi, a deep sea species of only 1. Rhincodon typus, the largest fish in the world, which reaches approximately 1. Sharks are found in all seas and are common to depths of 2,0. Modern sharks began to appear about 100 million years ago. Fossil mackerel shark teeth date to the Early Cretaceous. One of the most recently evolved families is the. Watch full Rugrats in Paris The Movie online full HD. Cartoon movies Rugrats in Paris The Movie online for free in HD. The film opens with a parody of Paramounts 1972. Getty. Although shark attacks are very rare, beach season is heating up, so PEOPLE spoke with Larry Cahoon, professor of biology and marine biology at the. They generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can survive and be found in both seawater and freshwater. Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics. They have numerous sets of replaceable teeth. Well known species such as the great white shark, tiger shark, blue shark, mako shark, thresher shark, and the hammerhead shark are apex predatorsorganisms at the top of their underwater food chain. Many shark populations are threatened by human activities. Etymology. Until the 1. This is still evidential in several species termed dogfish, or the porbeagle. The etymology of the word shark is uncertain, the most likely etymology states that the original sense of the word was that of predator, one who preys on others from the Dutch schurk, meaning villain, scoundrel cf. A now disproven theory is that it derives from the Yucatec Maya word xok, pronounced shok. Evidence for this etymology came from the Oxford English Dictionary, which notes shark first came into use after Sir John Hawkins sailors exhibited one in London in 1. Caribbean Sea. However, the Middle English Dictionary records an isolated occurrence of the word shark referring to a sea fish in a letter written by Thomas Beckington in 1. New World etymology. Evolution. Evidence for the existence of sharks dates from the Ordovician period, 4. Only scales have been recovered from the first sharks and not all paleontologists agree that these are from true sharks, suspecting that these scales are actually those of thelodont agnathans. The oldest generally accepted shark scales are from about 4. Silurian period. 9 The first sharks looked very different from modern sharks. The majority of modern sharks can be traced back to around 1. Most fossils are of teeth, often in large numbers. Partial skeletons and even complete fossilized remains have been discovered. Estimates suggest that sharks grow tens of thousands of teeth over a lifetime, which explains the abundant fossils. The teeth consist of easily fossilized calcium phosphate, an apatite. When a shark dies, the decomposing skeleton breaks up, scattering the apatite prisms. Preservation requires rapid burial in bottom sediments. Among the most ancient and primitive sharks is Cladoselache, from about 3. Paleozoic strata in Ohio, Kentucky, and Tennessee. At that point in Earths history these rocks made up the soft bottom sediments of a large, shallow ocean, which stretched across much of North America. Cladoselache was only about 1 metre 3. Replicants, superheros, and reboots await you in our Fall Movie Guide. Plan your season and take note of the hotly anticipated indie, foreign, and documentary. Its teeth had several pointed cusps, which wore down from use. From the small number of teeth found together, it is most likely that Cladoselache did not replace its teeth as regularly as modern sharks. Its caudal fins had a similar shape to the great white sharks and the pelagic shortfin and longfin makos. The presence of whole fish arranged tail first in their stomachs suggest that they were fast swimmers with great agility. Most fossil sharks from about 3. The Xenacanthida was almost exclusive to freshwater environments. By the time this group became extinct about 2. The other group, the hybodonts, appeared about 3. The results of a 2. Megalodon top two, estimated maximum and conservative sizes with the whale shark, great white shark, and a human for scale. Modern sharks began to appear about 1. Fossil mackerel shark teeth date to the Early Cretaceous. One of the most recently evolved families is the hammerhead shark family Sphyrnidae, which emerged in the Eocene. The oldest white shark teeth date from 6. In early white shark evolution there are at least two lineages one lineage is of white sharks with coarsely serrated teeth and it probably gave rise to the modern great white shark, and another lineage is of white sharks with finely serrated teeth. These sharks attained gigantic proportions and include the extinct megatoothed shark, C. Watch The Tesseract IMDB. Like most extinct sharks, C. This giant shark reached a total length TL of more than 1. C. megalodon may have approached a maxima of 2. Paleontological evidence suggests that this shark was an active predator of large cetaceans. Taxonomy. Sharks belong to the superorder Selachimorpha in the subclass. Elasmobranchii in the class. Chondrichthyes. The Elasmobranchii also include rays and skates the Chondrichthyes also include Chimaeras. It is currently thought that the sharks form a polyphyletic group some sharks are more closely related to rays than they are to some other sharks. The superorder Selachimorpha is divided into Galea or Galeomorphii, and Squalea or Squalomorphii. The Galeans are the Heterodontiformes, Orectolobiformes, Lamniformes, and Carcharhiniformes. Lamnoids and Carcharhinoids are usually placed in one clade, but recent studies show the Lamnoids and Orectoloboids are a clade. Some scientists now think that Heterodontoids may be Squalean. The Squaleans are divided into Hexanchoidei and Squalomorpha. The Hexanchoidei includes the Hexanchiformes and Chlamydoselachiformes. The Squalomorpha contains the Squaliformes and the Hypnosqualea. The Hypnosqualea may be invalid. It includes the Squatiniformes, and the Pristorajea, which may also be invalid, but includes the Pristiophoriformes and the Batoidea. There are more than 4. Carcharhiniformes Commonly known as ground sharks, the order includes the blue, tiger, bull, grey reef, blacktip reef, Caribbean reef, blacktail reef, whitetip reef, and oceanic whitetip sharks collectively called the requiem sharks along with the houndsharks, catsharks, and hammerhead sharks. They are distinguished by an elongated snout and a nictitating membrane which protects the eyes during an attack. Heterodontiformes They are generally referred to as the bullhead or horn sharks. Hexanchiformes Examples from this group include the cow sharks and frilled sharks, which somewhat resembles a marine snake. Lamniformes They are commonly known as the mackerel sharks. They include the goblin shark, basking shark, megamouth shark, the thresher sharks, shortfin and longfin mako sharks, and great white shark. They are distinguished by their large jaws and ovoviviparous reproduction. The Lamniformes also include the extinct megalodon, Carcharodon megalodon. Orectolobiformes They are commonly referred to as the carpet sharks, including zebra sharks, nurse sharks, wobbegongs, and the whale shark. Pristiophoriformes These are the sawsharks, with an elongated, toothed snout that they use for slashing their prey. Squaliformes This group includes the dogfish sharks and roughsharks. Squatiniformes Also known as angel sharks, they are flattened sharks with a strong resemblance to stingrays and skates. Cladoselachiformes Hybodontiformes Symmoriida Xenacanthida XenacantiformesAnatomy. Shark Attack Survivor Paul de Gelder Talks Shark Week Special Great White Matrix. As an Australian Navy diver, Paul de Gelder is used to stressful situations, but five and a half years ago, he faced one of his few fears right in the jaws. De Gelder was participating in a work exercise in the waters near Sydney Harbor when he was attacked by a shark. The diver miraculously survived the terrifying encounter, but the injuries from the attack cost him his right hand and leg. Instead of letting the trauma keep him out of the water, de Gelder re qualified for the Navy with his new prosthetics and began to study sharks. Now, the diver has joined up with underwater cameraman Andy Casagrande for the Discovery Shark Week special Great White Matrix. For the project, the pair dive among some of the worlds scariest animals to learn more about their predatory behaviors and what causes some sharks to go after people instead of fish. De Gelder took a break from the frenzy of Shark Week to talk to PEOPLE and share his harrowing story, shark attack tips and what to expect from the toothy giants of Great White Matrix. Watch the brave divers full shark story in the video above, and read on to see why de Gelder is now defending the same animal that took his hand and leg. Tune in to the Discovery Channel on Saturday, Aug. Gelders special Great White Matrix. Since the attack, how has your relationship with sharks changed Its changed in every aspect. Before, I was petrified of sharks. I was afraid of being anywhere near them. The big sharks, with the big teeth, which sometimes bite us I was absolutely terrified of them, especially spending so much time in the water as a Navy diver. Now, Ive had the opportunity to go to the United Nations and talk about shark conservation, of all things. And that happened through an opportunity with PEW, who approached me and said, Would you come and talk on the behalf of sharks I just thought, Hell yeah, free trip to New York But when they gave me the paperwork and the things I need to know about, I started to realize how important they are to the ocean, how essential they are to the ecosystems. They keep they oceans healthy. So I jumped on board and just continued to learn more and more. Now, its at the point where my name is affiliated with sharks and Shark Week. I get my own show to host with Andy. The sharks and I have become quite good friends. Whats the biggest misconception people have about sharks The biggest misconception is that sharks are after humans, and that they want to eat us and are extremely dangerous. If people knew how much sharks were actually around us when we are in the water, they probably wouldnt go in. In the show we go to this place that we discovered was a great white nursery. There were great white sharks everywhere. The families that were going there on vacation coexisted with them. There were people going out surfing, and no one was getting attacked. The biggest misconception is that they want to eat us. Were not on the menu. As someone who studies sharks, what is the one thing you want to know about them that experts have yet to discover I wonder if they have a consciousness. If they are thinking, and calculating. Some of the great whites in the show, the big ones, were coming up to the surface of the water and doing this thing called eye popping, where they stick their heads out of the water and look at us. You could see the eye rotating, and looking at us, and taking everything in, and processing. So I would really like to know if they are cognitive, or if they are just animals going off instinct. You said before the attack you were afraid of them, so when the day finally arrived, and you realized this was happening to you, how did you survive it A lot of things came into play that day. I think my medical training through the military being put in stressful environments continuously was part of it. The fact that I was super fit, and my body could function on lowered amounts of oxygen and blood, the medical training of my buddies, who did the first aid, all played a role. I asked the doctor, Why am I still aliveHow did I survive all this and he looked at me in all seriousness and said, Its because you have a big heart. I think I was just extremely lucky to have all those factors combined on that one day. Do you remember the exact day Yeah. Ive talked about it so many times now as Ive traveled around the world doing motivational speaking, that I relive it all the time. When I do that, I dont just want it to be a blas type thing. I want people to feel how I was feeling, so I give it all my emotion and relive that for them. Its hard work, but its worth it. Describe the most memorable shark adventure you had while taping your specials. Besides the shark attack, and seeing my first great white, for this show Great White Matrix, it would be going to Fiji and diving for the first time without a cage with bull sharks. And hand feeding a bull shark. What did you feed it I fed it a fish head. We were filming for 6. Minutes, it was the last dive of the last day. It was only me, the cameramen and the boss diver. I wasnt supposed to be allowed to do it, but we were getting called up and I was like, This is my last chance, so I ducked in the bucket, grabbed a big fish head, and held it out there. And this humongous bull shark came through, opened its mouth and just sucked the fish head right out of my hand. What do you do with your fingers at that point, when the shark comes up Your arm just retracts into your body. What work with sharks do you have planned for the future I have a couple of offers for filming more shark documentaries, so I am looking forward to getting into that, learning more and teaching more. The more chances I have to get paid to go dive with sharks and have adventures with sharks, the happier I am. RELATED Happy Shark Week Our Six Favorite Shark Videos of 2.