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Fast Facts about Tiger Sharks
Galeocerdo - is from the Greek words "Galeos" and "Kerdo" which mean "Shark" and "Fox", or the "Fox Shark"
The Common name is the "Tiger Shark"
The species name Cuvier is named after the naturalist who described the shark.
Taxonomy: Tiger sharks are in the Carcharhiniformes order, and belong to the Carcharhinidae family.
Order: Carcharhiniformes Family: Carcharhinidae (Requiem Sharks) Genus: Galeocerdo Species: Cuvier.
Age: Eocene to Recent
Tiger sharks first appear in the fossil record in the Eocene as Galeocerdo latidens.
Today there is one living species of tiger shark, Galeocerdo cuvier.
Distribution: Global - Temperate and Tropical Waters
Tiger sharks are found in tropical and temperate waters across the globe, including the Pacific. The only place they do no occur in temerate waters is in the Mediterranean Sea.
Tiger sharks are large sharks with an unmistakable appearance as they have very short and blunt snouts. They also have a unique color pattern. At birth, Tiger sharks have dark spots along their dorsal surface, which fuse into vertical bars or stripes at maturity. These unique stripes begin to fade as the shark ages.
Body Size: Large
Tiger sharks are large sharks. Their average lengths are around 11 - 14 feet. Large specimens can reach up to 18 feet in length.
Tiger sharks have unique looking teeth, they are short, wide, and robust looking. The blades are covered with serrations.
Diet: Almost Anything!
Tiger sharks have been known to eat just about anything, Bony fish, other sharks, dolphins, sea turtles, to squid, and crustaceans.
The IUCN has the Tiger shark listed as lower risk or near threatened.
Tiger sharks have been found with very weird things in their stomachs, including car license plates, tires, and even a chicken coop complete with chickens!
Tiger Sharks: The Details
The Tiger shark, Galeocerdo genus, made its first appearance in the Eocene as G. latidens. G. latidens was a smaller Tiger shark with a proportionately wider root than other Tiger species. By the Oligocene, G. aduncus became the main tiger shark. This species became extinct in the late Miocene. It is replaced by G. cuvier in the Pliocene. G. cuvier is now the only extant Tiger species.
G. cuvier, Modern Tiger sharks, are among the largest sharks; lengths of 3.35 m - 4.25 m (11 - 14 ft) are common,
while the largest specimens are believed to exceed 5.5 m (18 ft) (Castro, p.125). Because Tiger sharks have a unique
Tiger stripe pattern, they are easy to identify and often referred to as the spotted shark or leopard shark. As pups,
they have dark spots along their dorsal surface, which fuse into vertical bars or stripes at maturity. These unique stripes
begin to fade as the shark ages (Castro, p.125). Tiger sharks also have very short, blunt snouts. These characteristics make
it very difficult to misidentify a Tiger shark.
Tiger sharks are found in all subtropical and warm temperate seas (Compagno, p.283). They prefer coastal areas, and are commonly found in river estuaries and harbors. In North America, they are found from Massachusetts down to the Gulf of Mexico and the Caribbean. On the Pacific side, they are found in Hawaii, and southward from Southern California. They are also known to seasonally migrate, moving from temperate to tropical waters in the winter; they also make long migrations between islands in the Pacific. Tiger sharks are not found in the Mediterranean Sea.
Tiger sharks are solitary nocturnal hunters and feeders. They will eat just about anything! Their diets include bony fishes, sharks, rays, dolphins, turtles, crabs, squid, birds, and even garbage (Castro, p.126). Tiger sharks are also known to prey on humans. They are second only to the Great White Shark in number of reported attacks on humans. However, please remember, a shark attack is a very rare event; normally these creatures will stay away from humans.
This shark has very little commercial value other than its jaws in souvenir shops. Some countries, however, use the shark for its fins. It is also classified as a game fish and loved by sports fisherman. The International Union for Conservation of Nature and Natural Resources (IUCN) has the Tiger shark listed as lower risk / near threatened.
For ancient native Hawaiians, sharks played a very spiritual role. They were considered "na aumakua" or ancestor spirits. The larger sharks, the
Tiger sharks and Great Whites were called "niuhi." Eating the eyes of niuhi gave chiefs special intuition. Women were not allowed to eat niuhi.
Besides for being spiritual beings, shark skin and teeth had many uses. Specifically, Tiger shark teeth were often crafted onto wood and used as knives and other cutting instruments. They were even attached to war clubs, and other weapons. These artifacts can be seen in the Bishop Museum in Oahu. This image shows a replica weapon.
P. contortus aka G. contortus, although similar looking to the tiger sharks,
it is probably not related to the Galeocerdo genus.
Although the teeth have a similar shape, the design is different. Galeocerdo teeth have serrations enabling a cutting design. P. contortus teeth have slender, twisted crowns with very fine serrations. This shape is better suited for grasping, not cutting. As a result, P. contortus would have probably had a diet of a diet of small bony fish and rays.
The Physogaleus genus first appeared in the Eocene as a small shark called P. secundus. This genus continued to evolve into the Oligocene, and finally into the Miocene, where it became extinct. The last species of this genus is P. contortus. It is a short lived species that appeared in the late Oligocene and became extinct in the late Miocene.
Tiger Shark Teeth Morphology/ Identification:
G. cuvier, G. aduncus, and P. contortus
G. cuvier is the extant (living) Tiger shark. These teeth are unmistakable. G. cuvier teeth are the largest of all species of Tiger shark, and are very robust looking. They have an average length of approximately 2.9 cm (1.1") and an average height of approximately 2.2 cm (.86") (Purdy et al, p.149). Tiger teeth have complex serrations on their mesial cutting edges, and serrated distal cutting edges that are strongly notched. These teeth are ideal for a cutting dentition. The roots of Tiger teeth are flattened with square-like root lobes (Cocke, p.60).
While sharks of the carcharhinid family generally have upper teeth that are designed to cut and lower teeth that are designed to grasp, Tiger sharks have rows of almost identical teeth in both their upper and lower jaws.
This creates a nightmare for the average fossil collector trying to identify upper teeth from lower teeth. Purdy et al identifies very slight differences in Tiger shark upper and lower teeth. In lower teeth, the tips of the crowns usually have a slight lingual bend, lower teeth have a slightly developed Taurus on the root, and the arch formed by the lower root is often asymmetrical (Purdy et al p.149). For upper teeth, they can have a noticeable labial curvature, and the arch formed by the lower root is usually more symmetrical (Purdy et al p.149).
You may have noticed the use of words such as "usually," "can," and "often," this means not all teeth exhibit these characteristics. If you try and separate your uppers from lowers, good luck! I have been unsuccessful at separating most of my Tiger shark teeth.
Below is a diagram of a G. cuvier tooth showing the terminoligy, and also an image of different tooth positions.
Although tooth positions of tiger teeth appear very similar, the above image shows just how
different tooth positions actually are.
The first left two are either symphysial or parasymphysial teeth, the middle two are laterals, and the right two teeth are posteriors, .
G. aduncus is and extinct species that appeared in the Oligocene and became extinct in the late Miocene. This species of Tiger shark probably looked like a miniature, but less robust version of G. cuvier. Below is a diagram of a G. aduncus tooth.
Galeocerdo aduncus tooth from Aurora, NC
Physogaleus contortus aka Galeocero contortus
P. contortus is an extinct Tiger-like shark that, as with G. aduncus, appeared in the Oligocene and became extinct in the late Miocene. This shark had a very different tooth form. They are similar in size to G. aduncus, but have thicker roots. Their crowns are, however, slender and twisted; ideal for a grasping dentition. These sharks are very common in the Miocene. Below is a diagram of a P. contortus tooth.
Contortus Shark Dentition
The following image is my composite dentition of P. contortus from countless teeth collected along the Calvert Cliffs of Maryland. It was reconstructed based on a picture of a composite dentition from the Lee Creek III book (Purdy et al, p.147).
Fossil Tooth Bite/Feeding Pathologies
A few collected contortus teeth have the mesial cutting edges completely sheared off. This type of feeding damage is very easy to recognize.
The following image shows three teeth with this specific damage.
When studying the morphology of tiger teeth, a probable reason emerges. Since the interior angle between the root base and the mesial cutting edge is acute, any excessive stress, such as biting into bone, would channel enough force to easily sheer off the mesial cutting edge. This type of feeding damage can also be seen in Hemepristis teeth, which have a similar acute interior angle.
P. contortus teeth that have their mesial cutting edges sheered off. The left two are from the Calvert Cliffs of MD, and the right one is from Aurora, NC.
Recommended Books and Educational Materials about Tiger Sharks
As an educator, I get to sort through many educational books and supplies. Below are my two recommendations:
Sharks of the World (Princeton Field Guides)
By: Leonard Compagno et al, 2005
If you are into sharks and don't have a book by Compagno, you are missing out! He is the one that cataloged the sharks for the FAO species catalogue.
He is very thourough and not overly technical, which is a rarity! This book has full over 400 accurate and full color illustrations of all the known shark species plus a bunch on undescribed ones. The illustrations are done by Mark Dando, which is probably the best shark artist out there.
It also goes over shark biology, life history, and shark/human interactions. It's should be the main reference for anyone interested in sharks.
There is now an update to this book: Sharks of the World: A Fully Illustrated Guide , 2013. It's a hard cover, updated, and beefed up version of the 2005 book. It's a little pricier, but worth it!
Tiger Shark Jaw (Teaching Quality Replica)
This is a 20.1 by 20.5 inch replica Tiger Shark Jaw. If you like sharks and want a cool conversation piece on you wall, this is it! The company also has Great White replica jaws.
Species of fossil Tiger shark teeth are found in almost any marine Oligocene to Recent deposits.
These include deposits along the entire east coast of the United States.
Places to find them include the Chesapeake Bay Area (Calvert Cliffs Site), North Carolina (Aurora Site), and Florida (Venice Site).
Fossil Examples: G. cuvier, G. aduncus, P. contortus
Galeocerdo cuvier: Tiger Shark
This is the extant (living) Tiger shark. It's found in Pliocene fossil deposits
The rightmost two are labial views. All others are lingual views. These are from
Age:Pliocene: 2.5-5 m.y.
Location:PCS Mine, Aurora, NC
Size: largest one has a ~1 1/4" slant (32mm)
A worn Green's Mill Run tooth.
Formation:?Reworked from Yorktown?
Age:Pliocene ~2.5-5 m.y.
Location:Green Mill Run in North Carolina
Size: 3/4" (~19mm)
Date:Oct 2006 Trip
Galeocerdo aduncus (Agassiz, 1843) Extinct Tiger Shark
This species lived from the Oligocene into the Miocene.
This extinct species is much smaller and less robust looking than the extant (living) Tiger shark (G. cuvier).
These teeth are abundant in the Pungo River Formation at Aurora, NC and the Miocene Calvert formation in MD and VA.
The two leftmost teeth are labial views, all others are lingual views.
These are much less common than grey shark teeth, and, if you're not careful, they can easily be confused with them.
However, notice the deep notch in the roots, also there are no serrations present on the teeth.
Formation: ?Pungo River
Age: ?~18-22 m.y.
Location:PCS Mine, Aurora, NC
Size: largest is 11/16" (17mm)
Right two are lingual views.
Notice the coarse serrations on the enameloid shoulders.
Uppers and lowers are very difficult to tell apart, these are arranged in no particular order.
Formation: Calvert, Plum Point member
Age: Early - Middle Miocene ~ 18-15 m.y.
Location: Randle Cliff, Calvert Co., Maryland
Size: usually ~ 1/2-3/4" (13-19mm)
This one is from South Carolina
Formation: Chandler Bridge fm.
Age: Oligocene ~28 m.y.
Location: Lowcountry of South Carolina
~5/8" (~ 15mm)
Date:: Aug 2006 Trip
Physogaleus contortus - Extinct Tiger-Like Shark
Purdy et al (2001).
This species of Tiger Shark is very common along the U.S. East Coast deposits, but rarely found along the U.S. West Coast deposits. This species Lived from the upper Oligocene and became extinct in the Miocene.
There are a few big differences between these and G. aduncus. First, the crowns are twisted, looking pathological, as shown in the profile view. Also, the enameloid shoulder has very fine serrations, unlike the coarse serrations of G. aduncus. This slender tooth form probably means the contortus fed on bony fish, while the aduncus and extant cuvier species fed on a wider variety of prey. This extinct species is also smaller than the extant (living) Tiger shark (G. cuvier).
The bottom right two are labial views. All others are lingual views
Age:Roughly 18-22 m.y.
Location:PCS Mine, Aurora, NC
Size: largest one has a ~ 7/8" slant (22mm)
The small upper teeth in the center are parasymphyseals. The lower right-most tooth is a posterior. The rightmost
upper and lower teeth are lingual views.
The roots on lower contortus teeth are more robust than the roots on uppers. However, laterals and anterio-laterals are very difficult to tell apart.
Formation: Calvert, Plum Point member
Age: Early - Middle Miocene ~ 18-15 m.y.
Location: Randle Cliff, Calvert Co., MD
Size: ~ 5/8 to 7/8" (16 - 22mm)
Castro, Jose L. (1996). Sharks of North American Waters. College Station: Texas AandM University Press.
Hamlett, William C, ed. (1999). Sharks, skates, and rays : the biology of elasmobranch fishes. Baltimore : Johns Hopkins University Press.
Michael, Scott W. (1993). Reef sharks and rays of the world : a guide to their identification, behavior, and ecology. Monterey, CA.: Sea Challengers.
Purdy, R., Schneider, V., Appelgate, S., McLellan, J., Meyer, R. & Slaughter, R. (2001). The Neogene Sharks, Rays, and Bony Fishes from Lee Creek Mine, Aurora, North Carolina. In: Geology and Paleontology of the Lee Creek Mine, North Carolina, III. C. E. Ray & D. J. Bohaska eds. Smithsonian Contributions to Paleobiology, No 90. Smithsonian Institution Press, Washington D.C. pp. 71-202.