Sharksonline's Blog

Above cretoxyrhina

1. Cretoxyrhina is all so known as the Ginsu Shark. The Ginsu shark is the most well understood fossil sharks to date. A few preserved part have revealed a great deal of insight about the physical features and lifestyle of this ancient shark.

2. Cretoxyrhina was a large shark that lived during the Cretaceous period, about 100 to 82 million years ago.

3. The fossil teeth of Cretoxyrhina are up to 7 cm long, curved and smooth-edged, with a thick enamel coating.

4. Cretoxyrhina grew up to 7.5 meters (25 ft) long and was larger than the great white shark.

5.The Ginsu shark was the largest shark in its time and was among the top predators of the seas. Fossil records revealed that it preyed upon a number of marine animals such as, Mosasaurs, Plesiosaurs, Xiphactinus, and protostegid turtles.

6. The specimen from Niobrara Chalk of western Kansas supports the idea that the body of the Ginsu shark looks like the great white shark. The caudal fin morphology of the Ginsu shark was an active shark and capable of fast swimming so the believe.

7. The Ginsu shark lived in Cenomanian–Campanian seas worldwide and including in the Western Interior Seaway of North America.

All of this info is from http://en.wikipedia.org/wiki/Ginsu_Shark

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Well a few days ago my dad got me a baby megalodon tooth. My megalodon lived 2 to 5 millions years ago. And is 3 and a half centimeters.

Here are some photos

Above the basking shark

1. This shark is called the basking shark because it is most often observed when feeding at the surface and appears to be basking in the warmer water there.

2. The basking shark is found worldwide in warm waters and cold waters. But it prefers 8 to 14 °C (46 to 57 °F) temperatures, but recently has been confirmed to cross the much-warmer waters at the equator. It is often seen close to land, including bays with narrow openings. The shark follows plankton and therefore often visible at the surface. The basking shark is found from the surface down to at least 910 meters (2,990 ft).

3. The largest accurately measured was trapped in a herring net in the Bay of Fundy, Canada in 1851. Its total length was 12.27 metres (40.3 ft) and it weighed an estimated 19 short tons (17 t). Normally the basking shark reaches a length of between 6 metres (20 ft) and a little over 8 metres (26 ft). Some specimens surpass 9–10 metres (30–33 ft) but after years of large-scale fishing, specimens of this size have become rare.

4. Studies in 2003 proved that basking sharks do not hibernate, showing that they are active year-round. In winter, basking sharks move to depths of up to 900 metres (3,000 ft) to feed on deep water plankton.

5. Tagging confirms that basking sharks move thousands of kilometres during the winter, seeking plankton. It also found that basking sharks shed and renew their gill in an ongoing process, rather than over a short period. A 2009 study tagged 25 sharks and at least some migrate south for the winter. Remaining at depths between 200 metres (660 ft) and 1,000 metres (3,300 ft) for many weeks, the tagged sharks crossed the equator to reach Brazil. One individual spent a month near the mouth of the Amazon River. It is unknown why they undertake this journey. Some suspects it may to breed. And do not approaching boats (unlike great white sharks). They are harmless to humans if left alone and are not attracted to chum.

6. Basking sharks are social animals and usually in small numbers (3 or 4) but reportedly up to 100 individuals. Their social behavior is thought to follow visual cues. Although the basking shark’s eyes are small, they are fully developed. They may visually inspect boats. Females are thought to seek shallow water to give birth. These sharks have few predators but orcas and tiger sharks feed on them. Although it is unlikely that they are able to cut through the shark’s thick skin.

7. The basking shark feeds on plankton, small fish. They feed at or close to the surface with their mouths wide open. It relies only on the water that it pushes through its gills by swimming so it breath and feed at the same time.

8. Basking sharks developing embryos first rely on a yolk sac. Their seemingly useless teeth may play a role before birth in helping them feed on the mother’s unfertilized ova (a behaviour known as oophagy). Gestation is thought to span over a year (perhaps 2 or 3 years), with a small though unknown number of young born fully developed at  (4 ft to 6 ft). Mating is thought to occur in early summer and birthing in late summer, following the female’s movement into shallow waters. The age of maturity is not known but is thought to be between the ages of 6 and 13 and at a length of 4.6–6 metres (15–20 ft). Breeding frequency is also unknown, but is thought to be 2 to 4 years.

All of this info is from http://en.wikipedia.org/wiki/Basking_shark

Above the spiny dogfish shark

1. The spiny dogfish has dorsal spines, no anal fin, and white spots along its back. These are used defensively but if captured, the shark can arch its back to pierce its captor. Glands at the base of the spines secrete a mild poison.

2. Males mature at around 11 years of age, growing to 80–100 cm (2.6–3.3 ft) in length and females mature in 18–21 years and are a bit larger than males, reaching 98.5–159 cm (3.23–5.22 ft).

3. Both sexes are greyish brown color.

4. Mating takes place in the winter months with gestation lasting 22–24 months. Litters range between 2 and 11 but average 6 or 7 pups.

5. It is found mostly in shallow waters and further offshore in most parts of the world, especially in temperate waters.

In blue this is where it lives

All of this info is from http://en.wikipedia.org/wiki/Spiny_dogfish_shark

Above the dwarf lanternshark

1. At present time the dwarf lanternshark has only been reported from a small area of the Caribbean Sea and off the coasts of Colombia and Venezuela, occurring between Barranquilla and Santa Martaand near the Guajira Peninsula and between the Los Testigos Islands and Grenada. This shark can live at depths of 283–439 m (928–1,440 ft).

2. The dwarf lanternshark has a long wide, flattened head. The eyes are large. The nares are large and preceded by poorly developed flaps of skin. There are 25–32 tooth rows in the upper jaw and 30–34 tooth rows in the lower jaw. The five pairs of gill slits are small. The skin is densely covered by thin, needle-like dermal denticles in a random pattern, except for the lips and the tips of the fins. This shark is dark brown with a striking pattern of black markings on its ventral surface and broken fine black line along the middle of its back, a black band on the end of its caudal fin and a dark blotch on its lower caudal fin lobe. The largest known individual is 21.2 cm (8.3 in) long.

3. Perhaps the smallest living shark species, male dwarf lanternsharks mature at a length of 16–17.5 cm (6.3–6.9) and females from a length of 15.5 cm (6.1) with 19–20 cm (7.5–7.9) long pregnant individuals known. This species is ovoviviparous, with the developing fetuses being sustained by a yolk sac until birth. Females bear litters of 2–3 young, each measuring 5.5–6.0 cm (2.2–2.4 in) long.

All of this info is from http://en.wikipedia.org/wiki/Dwarf_lanternshark

Above the Whale shark

1. The whale shark inhabits all tropic and warm-temperate seas. Although typically seen offshore, it has been found closer to land, entering lagoons or coral atolls and near the mouths of estuaries and rivers. It is capable of diving to depths of 700 meters (2,300 ft), and is migratory.

2. As a filter feeder it mouth which can be up to 1.5 meters (4.9 ft) wide and can contain between 300 and 350 rows of tiny teeth. It has five large pairs of gills. Two small eyes are located towards the front of the shark’s wide, flat head. The body is mostly Grey with a white belly and three prominent ridges run along each side of the animal and the skin is marked with a “checkerboard” of pale yellow spots and stripes. These spots are different to each individual and are useful for counting populations. Its skin can be up to 10 centimeters (3.9 in) thick. The shark has a pair each of dorsal fins and pectoral fins. The whale shark is not a fast swimmer since it uses its entire body, usually for fish and has an average speed of only around 5-kilometer-per-hour (3.1 mph). The largest specimen was caught on November 11, 1947, near the island of Baba, not far from Karachi, Pakistan. It was 12.65 meters (41.50 ft) long, weighed more than 21.5 tonnes (47,000 lb).

3. The whale shark is a filter feeder  one of only three known filter feeding shark species. It feeds on macro-algae, plankton, krill, Christmas Island red crab larvae and small squid. The shark sucks in a mouthful of water, closes its mouth and expels the water through its gills. During the slight delay between closing the mouth and opening the gill flaps, plankton is trapped  in the mouth and then gets eating. Whale sharks have been observed “coughing” and it is presumed that this is a method of clearing a build up of food particles in the gill. Whale sharks migrate to feed and possibly to breed. The whale shark is an active feeder, targeting plankton or fish.

4. The whale shark, despite its size, does not pose danger to humans. Whale sharks are great for an example when educating the people about them and there sharks. They are actually quite gentle and can play with divers. Divers and snorkelers can swim with this giant fish without risk apart from blows from the shark’s large tail fin. The shark is seen by divers in many places around the world

5. The capture of a female in July 1996 which was pregnant with 300 pups. And know we known that the eggs remain in the body and then females give birth to live young pups which are 40 to 60 centimeters (16 to 24 in) long. It is believed that they reach sexual maturity at 30 years old and the life span of a whale shark  is estimated to be 70 to 100 years old.

All of this info is from http://en.wikipedia.org/wiki/Whale_shark

Above the Lemon shark

1. The lemon shark is found mainly along the subtropical and tropical parts of the Atlantic coast of North and South America and around Pacific Islands. The longest lemon shark recorded was 13 ft long but they are usually 8 to 10 ft (3.0 m). They like tropical water and like to stay at moderate depths.

2. Lemon sharks females giving birth to between 4 and 17 pups every other year in warm and shallow lagoons. The young pups have to fend for themselves and remain in shallow water near shallow water until they grow larger. At maturity at a size of 1.5 to 2 m and an age of 12 to 15 years they leave shallow water and move into deeper waters offshore. However little is known of this life stage. Maximum recorded length and weight is 340 cm and 183 kg.

3. Lemon sharks are a popular choice for study by scientists as they survive well in captivity, unlike many other species. The species is the best known of all sharks in terms of behaviour and ecology. There have been 22 known lemon shark attacks since 1580 with no deaths.

4. Lemon sharks are bottom dwellers but have very poor eyesight and cannot see well to find their food. However, they are have extremely sensitive and accurate sensors in the nose to find food.

All of this info is from http://en.wikipedia.org/wiki/Lemon_shark