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Shark Tooth
Sharks continually shed their teeth; some Carcharhiniformes shed approximately 35,000 teeth in a lifetime, replacing those that fall out. There are four basic types of shark teeth: dense flattened, needle-like, pointed lower with triangular upper, and non-functional. The type of tooth that a shark has depends on its diet and feeding habits. Sharks are a great model organism to study because they continually produce highly mineralized tissues. Sharks continually shed their teeth and replace them through a tooth replacement system. Through this system, sharks replace their teeth relatively quickly with replacement teeth that are ready to rotate because their teeth often get damaged while catching prey. They will replace teeth that are broken and young sharks can even replace their teeth weekly. Although sharks constantly shed their teeth, factors such as water temperature affect the turnover rate. While warmer water temperatures produced faster rates, cold water temperatures slow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Shark
The blue shark (''Prionace glauca''), also known as the great blue shark, is a species of requiem shark, in the family Carcharhinidae and the only member of its genus which inhabits deep waters in the world's temperate and tropical oceans. Averaging around and preferring cooler waters, the blue shark migrates long distances, such as from New England to South America. It is listed as Near Threatened by the IUCN. Although generally lethargic, they can move very quickly. Blue sharks are viviparous and are noted for large litters of 25 to over 100 pups. They feed primarily on small fish and squid, although they can take larger prey. Some of the blue shark’s predators include the killer whale and larger sharks like tiger sharks and the great white shark. Their maximum lifespan is still unknown, but it is believed that they can live up to 20 years. They are one of the most abundant pelagic sharks, with large numbers being caught by fisheries as bycatch on longlines and nets. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otodus Angustidens
''Otodus angustidens'' is an extinct species of prehistoric megatoothed sharks in the genus ''Otodus'', which lived during the Late Eocene and Miocene epochs about 34 to 21 million years ago. The largest individuals were about long. This shark is related to another extinct megatoothed shark, the famous ''Otodus megalodon''. Taxonomy The Swiss naturalist Louis Agassiz, first identified this shark as a species of genus '' Carcharodon'' in 1835. In 1964, shark expert, L. S. Glikman recognized the transition of '' Otodus obliquus'' to ''C. auriculatus'' and moved ''C. angustidens'' to genus ''Otodus''. (See "external links" below) However, in 1987, shark expert H. Cappetta recognized the '' C. auriculatus'' - ''C. megalodon'' lineage and placed all related megatooth sharks along with this species in the genus ''Carcharocles''. The complete ''Otodus obliquus'' to ''C. megalodon'' transition then became clear and has since gained the acceptance of many other experts with the passa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otodus Auriculatus
''Otodus auriculatus'' is an extinct species of large sharks in the genus ''Otodus'' of the family Otodontidae, closely related to the sharks of the genus ''Otodus'', and also closely related to the later species megalodon. The largest individuals were about long. Its teeth were large, having coarse serrations on the cutting edge, and also with two large cusplets. The teeth can reach up to , and belonged to a large "megatoothed" shark. Assignment to the genus ''Carcharocles'' rather than ''Otodus'' It is known that there is at least one genus in the family Otodontidae, that being ''Otodus''. But the names and number of the genera in Otodontidae is controversial and the family's accepted phylogeny varies among paleontologists in different parts of the world. In the US and Britain the most widespread genus name for otodontids with serrated teeth is ''Carcharocles'', and the owners of unserrated ones ''Otodus''. In countries of the former USSR, like Ukraine or Russia, all of thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter Feed
Filter feeders are aquatic animals that acquire nutrients by feeding on organic matters, food particles or smaller organisms (bacteria, microalgae and zooplanktons) suspended in water, typically by having the water pass over or through a specialized filtering organ that sieves out and/or traps solids. Filter feeders can play an important role in condensing biomass and removing excess nutrients (such as nitrogen and phosphate) from the local waterbody, and are therefore considered water-cleaning ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms. Filter feeders can be sessile, planktonic, nektonic or even neustonic (in the case of the buoy barnacle) depending on the species and the niches they have evolved to occupy. Extant species that rely on such method of feeding encompass numerous phyla, including poriferans (sponges), cnidarians (jellyfish, sea pens and corals), arthropods (krill, mysids and barnacles), molluscs ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whale Shark
The whale shark (''Rhincodon typus'') is a slow-moving, filter feeder, filter-feeding carpet shark and the largest known Extant taxon, extant fish species. The largest confirmed individual had a length of . The whale shark holds many records for size in the animal kingdom, most notably being by far the most massive living non-cetacean animal. It is the sole member of the genus ''Rhincodon'' and the only extant member of the family Rhincodontidae, which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984 it was classified as ''Rhiniodon'' into Rhinodontidae. Whale sharks inhabit the open waters of all tropical oceans. They are rarely found in water below . Whale sharks' lifespans are estimated to be between 80 and 130 years, based on studies of their vertebral growth bands and the growth rates of free-swimming sharks. Whale sharks have very large mouths and are filter feeders, which is a feeding mode that occurs in only two other sharks, the megamouth s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basking Shark
The basking shark (''Cetorhinus maximus'') is the second-largest living shark and fish, after the whale shark. It is one of three Planktivore, plankton-eating shark species, along with the whale shark and megamouth shark. Typically, basking sharks reach in length, but large individuals have been known to grow more than long. It is usually greyish-brown, with mottled skin, with the inside of the mouth being white in colour. The caudal fin has a strong lateral keel and a crescent shape. Other common names include bone shark, elephant shark, sailfish, and sunfish. The basking shark is a Cosmopolitan distribution, cosmopolitan Fish migration, migratory species found in all the world's temperate oceans. A slow-moving filter feeder, its common name derives from its habit of feeding at the surface, appearing to be basking in the warmer water there. It has anatomical adaptations for filter-feeding, such as a greatly enlarged mouth and highly developed gill rakers. Its snout is conica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolphins
A dolphin is an aquatic mammal in the cetacean clade Odontoceti (toothed whale). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the brackish dolphins), and possibly extinct Lipotidae (baiji or Chinese river dolphin). There are 40 extant species named as dolphins. Dolphins range in size from the and Maui's dolphin to the and orca. Various species of dolphins exhibit sexual dimorphism where the males are larger than females. They have streamlined bodies and two limbs that are modified into flippers. Though not quite as flexible as Pinniped, seals, they are faster; some dolphins can briefly travel at speeds of or leap about . Dolphins use their conical teeth to capture fast-moving Predation, prey. They have well-developed hearing which is adapted for both air and water; it is so well developed that some can survive even if they are blind. Some species are w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Lions
Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk on all fours, short and thick hair, and a big chest and belly. Together with the fur seals, they make up the family Otariidae, eared seals. The sea lions have six extant and one extinct species (the Japanese sea lion) in five genera. Their range extends from the subarctic to tropical waters of the global ocean in both the Northern and Southern Hemispheres, with the notable exception of the northern Atlantic Ocean. Sea lions have an average lifespan of 20–30 years. A male California sea lion weighs on average about and is about long, while the female sea lion weighs and is long. The largest sea lions are Steller's sea lions, which can weigh and grow to a length of . Sea lions consume large quantities of food at a time and are known to eat about 5–8% of their body weight (about ) at a single feeding. Sea lions can move around in water and at their fastest they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great White Shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large Lamniformes, mackerel shark which can be found in the coastal surface waters of all the major oceans. It is the only known surviving species of its genus ''Carcharodon''. The great white shark is notable for its size, with the largest preserved female specimen measuring in length and around in weight at maturity. However, most are smaller; males measure , and females measure on average. According to a 2014 study, the lifespan of great white sharks is estimated to be as long as 70 years or more, well above previous estimates, making it one of the longest lived Chondrichthyes, cartilaginous fishes currently known. According to the same study, male great white sharks take 26 years to reach sexual maturity, while the females take 33 years to be ready to produce offspring. Great white sharks can swim at speeds of 25 km/h (16 mph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammerhead Sharks
The hammerhead sharks are a group of sharks that form the family Sphyrnidae, named for the unusual and distinctive form of their heads, which are flattened and laterally extended into a cephalofoil (a T-shape or "hammer"). The shark's eyes are placed one on each end of this T-shaped structure, with their small mouths directly centered and underneath. Most hammerhead species are placed in the genus ''Sphyrna'', while the winghead shark is placed in its own genus, '' Eusphyra''. Many different—but not necessarily mutually exclusive—functions have been postulated for the cephalofoil, including sensory reception, manoeuvering, and prey manipulation. The cephalofoil gives the shark superior binocular vision and depth perception. Hammerheads are found worldwide, preferring life in warmer waters along coastlines and continental shelves. Unlike most sharks, some hammerhead species will congregate and swim in large schools during the day, becoming solitary hunters at night. Descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stingrays
Stingrays are a group of sea rays, a type of cartilaginous fish. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwater stingray), Urolophidae (stingarees), Urotrygonidae (round rays), Dasyatidae (whiptail stingrays), Potamotrygonidae (river stingrays), Gymnuridae (butterfly rays) and Myliobatidae (eagle rays). There are about 220 known stingray species organized into 29 genera. Stingrays are common in coastal tropical and subtropical marine waters throughout the world. Some species, such as the thorntail stingray (''Dasyatis thetidis''), are found in warmer temperate oceans and others, such as the deepwater stingray (''Plesiobatis daviesi''), are found in the deep ocean. The river stingrays and a number of whiptail stingrays (such as the Niger stingray (''Fontitrygon garouaensis'')) are restricted to fresh water. Most myliobatoids are demersal (inhabit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
