This week’s Featured Species goes by many names including the gray nurse, spotted rag tooth, ground shark, the slender-toothed shark, and the sand tiger shark (Carcharias taurus). These sharks are one of the most popular species in zoos and aquariums due to their hardy disposition and their ferocious looking teeth. Sand tigers definitely pack a WOW! factor (Tricas, et al., 1997).
The sand tiger’s teeth are long, sharp needle-like hooked teeth. Each tooth is comprised of a tall, slender cusp accompanied by two smaller lateral cusps (Parker, 2008). Their teeth are not serrated like a great white (Carcharodon carcharias), but instead have very smooth edges. These sharks feed primarily on slippery, soft-bodied prey items like bony fishes. Their smooth hooked teeth are ideal for piercing into these slippery prey items (Whitenack & Motta, 2010).
Sand tiger sharks are ovoviviparous, which means their young develop inside the mother’s womb. Sand tiger pups begin hunting young… very young. Sand tiger pups begin to hunt inside the womb! The largest embryo that develops their teeth first, begins to consume their brothers and sisters. This is known as embryophagy or intrauterine cannibalism, and sand tiger sharks are the only sharks known to exhibit this behavior (Skomal, 2016). Female sand tiger sharks also have two uterus. The female will deliver two pups, one from each uterus, every two years, each measuring nearly 3 feet in length!
Megabeeach (2008 December 13). Shark eats siblings in womb! [Video Clip]. Retrieve from https://www.youtube.com/
Sand tiger sharks have an unusual means to maintain buoyancy in the water. They are known to gulp air at the surface which allows them to hover easily in the water without expending much energy (Skomal, 2016). During the day, divers have encountered large numbers of sand tiger sharks hovering in the water column, moving very slowly along rocky outcroppings. These sharks are have a docile disposition unless provoked (Parker, 2008).
Authority: Rafinesque, 1810
Family: Odontadspididae; 3 species
Length: Maximum of 10.5 feet (3.2 m)
Weight: Up to 350 lbs (159 kg)
Habitat: Continental and island shelves and slopes, coastal waters, coral and rocky reefs, bays, and estuaries
Depth: Usually less than 500 feet (152 m)
Gestation: 9 – 12 months
Litter Range: 2 pups every 2 years
Home Range: Worldwide in tropical and temperate waters
Diet: Wide range of fishes and invertebrates
IUCN Status: Some populations are Critically Endangered, other populations are Vulnerable; taken by commercial and recreational fisheries, as well as be speardivers
( Pollard & Smith, 2009; Parker, 2008; Skomal, 2016)
Thanks for checking out this week’s Featured Species. If you missed last week’s whale shark species profile, be sure to check it out! I’ll be posting from La Paz, Baja California Sur, Mexico, where I’ll be working with whale sharks in the field over the next few weeks!
The new Ocean For Sharks Shop is open! There’s handmade ocean inspired plush animals, canvas paintings, and of course my children’s book, Winifred the Wondrous Whale Shark, available in print and PDF. Be sure to stop by. Remember proceeds benefit shark research and conservation with a donation to Project AWARE!
Remember you can make a difference for marine ecosystems by calling your Congress man or woman and tell them that you care about the quality of our waters! Sharks, rays, and other marine organisms cannot speak or be represented in Congress. They need your voice. Get involved and stand up for sharks. Until next time finatics.
Featured Image Source
National Geographic. (Author). (n.d.). Sand Tiger Shark Close Up [Digital Image]. Retrieved from https://nationalgeographic.com/
Parker, S. (2008). The encyclopedia of sharks (2nd ed.). Buffalo, NY: Firefly Books Ltd.
Pollard, D. & Smith, A. 2009. Carcharias taurus. The IUCN Red List of Threatened Species 2009: e.T3854A10132481.
Skomal, G. (2016). The Shark Handbook: The Essential Guide for Understanding the Sharks of the World. (2nd ed.). Kennebunkport, ME: Cider Mill Press.
Stevens, J. D. (Ed.). (1997). Sharks (6th ed.). New York: Facts on File.
Tricas, T. C., Deacon, K., Last, P., McCosker, J. E., Walker, T. I., & Taylor, L. (1997). The Nature Company Guides: Sharks and Rays. (L. Taylor, Ed.). Hong Kong: The Nature Company, Time Life Books.
Whitenack, L. B., & Motta, P. J. (2010). Performance of shark teeth during puncture and draw: Implications for the mechanics of cutting. Biological Journal of the Linnean Society, 100(2), 271–286.