| Sand sharks Temporal range:
| |
|---|---|
| |
| Sand tiger shark (Carcharias taurus) | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Subdivision: | Selachimorpha |
| Order: | Lamniformes |
| Family: | Odontaspididae J. P. Müller & Henle, 1839 |
Sand sharks, also known as sand tiger sharks, gray nurse sharks or ragged tooth sharks, are mackerel sharks of the family Odontaspididae. They are found worldwide in temperate and tropical waters. The three species are in two genera.
YouTube Encyclopedic
-
1/2Views:389 09744 857
-
Sand Tiger Sharks | SHARK ACADEMY
-
Pentair Kreepy Krauly Sand Shark Review
Transcription
It has perhaps the most confusing name of any shark, and a mouthful of razor-sharp, pointy teeth! I'm Jonathan Bird, and this is Shark Academy! It's known by many names: the Spotted Ragged Tooth shark, the Gray Nurse Shark, the Sand Tiger shark...but it's not a Sand Shark, it's not a Tiger shark, it's not a Nurse shark. It's a Sand Tiger Shark. Very confusing. In spite of the fact that it's called a Sand Tiger shark, it's not related to the Tiger shark at all...actually, it much more closely related to the White shark. The Great White Shark!!! When you see a Sand Tiger shark up close, you'll probably notice there's a mouth full of very intimidating-looking teeth. They're long, they're skinny, and they're pointy. These are teeth that are designed for catching small, slippery fish. They're not teeth designed for taking big bites. They're designed for just catching things and letting them not get away, so their teeth kind of act like the barb on a fish hook. So even though they look really aggressive, they're actually not the type of shark that typically would bite a human. So, because this shark looks really mean—but it's actually not mean at all—it's one of the most popular sharks for captivity in aquaria. It's one of the sharks you are most likely to see if you visit someplace like the New England Aquarium, or the Georgia Aquarium, or the Mystic Aquarium. As you know, sharks don't have swim bladders so they tend to sink. Most sharks just have to deal with it by swimming along and using their pectoral fins to keep them up off the bottom. But the Sand Tiger has evolved a very clever way of dealing with that. They go to the surface and they gulp air into their stomachs—so they treat their stomach almost like a swim bladder. The Sand Tiger shark is perhaps most famous for being one of the species of sharks that undergoes a reproductive practice known as Intrauterine Cannibalism. The female has a pair of uteruses, and each uterus starts out with about fifty baby Sand Tiger sharks in it, but guess what? The first one that reaches about four inches long eats all of his or her siblings! That's the cannibalism part. So, twelve months later, after the gestation is over and the baby sharks are born, out of fifty sharks in each uterus (that's a hundred sharks!) only TWO are born! That is weird! For some reason that nobody can explain, Sand Tiger sharks love to get together (what scientists call "aggregate") in various places around the world. There are places off North Carolina in the United States, places off South Africa, and places off Australia where the sharks just seem to gather at certain times of the year. And people think they are mating or something, but nobody has ever been able to figure out exactly what they are doing. They like to get together for human week. If you want to learn more about Sand Tiger sharks, we did a big expedition to try to figure out what they were doing on the wrecks off North Carolina. Click the link below and watch the adventure! Until next time, I'm Jonathan Bird and this is Shark Academy!
Description
The body tends to be brown with dark markings in the upper half. These markings disappear as they mature. Their needle-like teeth are highly adapted for impaling fish, their main prey. Their teeth are long, narrow, and very sharp with smooth edges, with one and on occasion two smaller cusplets on either side.[2] Sand sharks have a large second dorsal fin.[1] The sand shark can grow up to 3.2 m (10 ft) long, and most adults can weigh around 200 kg (440 lb). The average lifespan of both sexes is only about 7 years, though they may live longer in captivity.
Location and origins
The name sand shark comes from their tendency to migrate toward shoreline habitats, and they are often seen swimming around the ocean floor in the surf zone; at times, they come very close to shore. They are often found in warm or temperate waters throughout the world's oceans, except the eastern Pacific.[3] They also frequent the Mediterranean and Adriatic Seas at depths from 20 to 200 m (66 to 656 ft) and sometimes more.[4]
Behavior
The sand shark has a unique hunting strategy. It is able to gulp air from above the surface and collect the air in its stomach. This enables it to become buoyant and approach its prey virtually motionless. During the day, the sand shark stays mostly inactive, but at night, it becomes active and resumes hunting activities.[5] Its staple is small fish, but it eats crustaceans and squid, as well. It occasionally hunts in shivers (groups), and has even been known to attack full fishing nets.
Reproduction
Sand sharks only develop two embryos, one in each uterus. The largest and strongest embryos consume their siblings in the womb (intrauterine cannibalism) before each surviving pup is born.[6] It has one of the lowest reproduction rates of all sharks and is susceptible to even minimal population pressure, so it is listed as vulnerable and is protected in much of its range.[7]
Attacks on people
Sand sharks are not known to attack humans. If a person were to provoke a sand shark, it may retaliate defensively. Sand sharks are generally not aggressive, but harass divers who are spearfishing. In North America, wreck divers regularly visit the World War II shipwrecks to dive with the sharks that make the wrecks their home.[8]
Conservation
A recent report from the PEW Charitable Trusts suggests a new management approach used for large mammals that have suffered population declines could hold promise for sharks. Because of the life-history characteristics of sharks, conventional fisheries management approaches, such as reaching maximum sustainable yield, may not be sufficient to rebuild depleted shark populations. Some of the more stringent approaches used to reverse declines in large mammals may be appropriate for sharks, including prohibitions on the retention of the most vulnerable species and regulation of international trade.[9]
Species
The family contains three extant species, in two genera, as well as many extinct species in several genera. Recent mitochondrial DNA analysis of extant members has found the two extant members do not actually form a monophyletic clade. This family is therefore polyphyletic and in need of revision.[10]
- Genus Carcharias Rafinesque, 1810
- Carcharias taurus Rafinesque, 1810 (sand tiger shark) [11]
- Genus Odontaspis Agassiz 1838
- Odontaspis ferox A. Risso, 1810 (smalltooth sand tiger)
- Odontaspis noronhai Maul, 1955 (bigeye sand tiger)
- Subfamily Odontaspinae † Herman, 1975 [12]
- Genus Striatolamia † Glikman, 1964
- Genus Carcharoides † Ameghino, 1901
- Genus Parodontaspis † White, 1931
- Genus Priodontaspis † Ameghino, 1901
- Genus Pseudoisurus † Glikman, 1957
- Genus Synodontaspis † White, 1931
- Subfamily Johnlonginae † Shimada, 2015[13]
- Genus Johnlongia †
- Genus Pseudomegachasma † (Shimada, 2015)
References
- ^ a b Froese, Rainer, and Daniel Pauly, eds. (2009). "Odontaspididae" in FishBase. January 2009 version.
- ^ Bigelow, Henry B.; Schroeder, William C. (1953). Fishes of the Gulf of Maine. United States Government Printing Office. Retrieved 30 October 2011.
- ^ National Geographic (10 September 2010). "Sand Tiger Sharks". National Geographic. Archived from the original on July 7, 2007. Retrieved 8 December 2012.
- ^ the-shark-side-of-life.com. "Sand Sharks". The Shark Side of life.
- ^ "Sand Tiger Shark Profile". National Geographic. 10 September 2010. Archived from the original on July 7, 2007. Retrieved 17 May 2013.
- ^ Martin, Aidan. "Intrauterine Cannibalism in Sharks". elasmo-research.org. Retrieved 2 July 2015.
- ^ Rigby, C.L.; Carlson, J.; Derrick, D.; Dicken, M.; Pacoureau, N.; Simpfendorfer, C. (2021). "Carcharias taurus". IUCN Red List of Threatened Species. 2021: e.T3854A2876505. doi:10.2305/IUCN.UK.2021-2.RLTS.T3854A2876505.en. Retrieved 12 November 2021.
- ^ Decker, Robert. "Ghosts in the Graveyard: N.C. Shark Diving". ScubaDiving.com. Retrieved 17 June 2015.
- ^ "Considering Shark Biology in Management". pewtrusts.org. 2 July 2015. Retrieved 5 July 2015.
- ^ Vella, Noel; Vella, Adriana (2020-07-02). "The complete mitogenome of the Critically Endangered smalltooth sand tiger shark, Odontaspis ferox (Lamniformes: Odontaspididae)". Mitochondrial DNA Part B. 5 (3): 3319–3322. doi:10.1080/23802359.2020.1814886. PMC 7782878. PMID 33458146.
- ^ "Carcharias taurus, Sand tiger shark (Rafinesque 1810)". fishba.se. Retrieved 2023-02-23.
- ^ "Fossilworks: Odontaspinae". fossilworks.org. Retrieved 17 December 2021.
- ^ "SHIMADA, K. & POPOV, E.V. & SIVERSSON, M. & WELTON, B.J. & LONG, D.L. (2015) | Literature | Shark-References". shark-references.com. Retrieved 2016-05-21.
External links
- FishBase Family Odontaspididae - Sand tigers. fishbase.org
- Sand Tiger Shark School
- Sand Tigers Sharks
- Shark Info
- Scuba divers swim among the sharks, Fayetteville Observer
This page was last edited on 2 April 2024, at 22:53