Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Carcharhinidae
Genus: Galeocerdo
Species: Galeocerdo cuvier
Size:
The Tiger Shark is one of the largest sharks, with the longest individual ever measured having been a female 5.5 m (18.2 feet) in total length. The males of
this species are sexually mature between 226 and 290 cm (7.4 to 9.5 feet), while females mature at a maximum length of 250 to 350 cm (8.2 to 11.5 feet).
Distribution:
Circumglobal, occurring in all tropical and warm temperate seas.
Habitat:
This large shark is named fro the dark strips on its gray back, which pronounced in juveniles but become pale or disappear in large adults. Its wide
mouth, broad nose, barrel chest, and the slenderness at the base of its tail are distinctive. So, too, are its heavily serrated, cockscomb-shaped teeth.
These, combined with its jaw strength, allow it to cut the bodies of large sea turtles, as well as seals, sea lions, and cetaceans.
They are active at night, and enter shallow reefs and lagoons after dusk to feed. Adult tiger sharks are also reported to be more abundant in the
tropics, while immature and adolescent specimens are more common in subtropical seas. The tiger shark occurs from the intertidal zone, or ocean's
surface, to a depth of 305 m (1,007 feet).
Reproduction:
Tiger sharks are quite prolific, these sharks breed by internal fertilization (they are ovoviviparous) bearing 10 to 82 pups per litter after a 12 to
16 month gestation period and are fully independent upon birth . In both the northern and southern hemispheres mating occurs in spring, while pupping
takes place in the spring and summer. The tiger shark is the only ovoviviparous requiem shark. The young are 20-30" (50-75cm) at birth. There is
considerable geographical variation in the size at maturity. The tiger shark matures at from 7 to 10 years of age, depending on the geographical
location, and may live as long as 45 to 50 years.
Feeding:
Omnivorous. One of the few species of shark that is a true scavenger. It consumes a wide range of marine prey including fish, crustaceans and cephalopods,
as well as birds, mammals, reptiles, turtles, and sea snakes. It also has been known to consume indigestable objects. Its wide mouth, broad nose, barrel
chest, and the slenderness at the base of its tail are distinctive. So, too, are its heavily serrated, cockscomb-shaped teeth. These, combined with its
jaw strength, allow it to cut the bodies of large sea turtles, as well as seals, sea lions, and cetaceans. Though the tiger has excellent eyesight, it
relies mostly on its acute sense of smell, which enables it to detect the faintest traces of blood. Their electroreceptors are sensitive to
low-frequency pressure waves produced by movements in the water, allowing these sharks to track prey in the absence of light. Once the prey is
located, the tiger shark circles and nudges it before making the kill. They are active at night, and enter shallow reefs and lagoons after dusk
to feed. In certain areas they migrate between island groups to take advantage of colonies of young birds learning to fly over water. Generally,
tiger sharks are sluggish, but they can move quickly when feeding,
Behavior:
Tiger sharks are solitary and nomadic. They often travel up to fifty mile in a day, stopping only to feed and can attain speeds greater than 20 miles
an hour. Although they appear sluggish, tigers become very active and vicious when stimulated with food. During the day adult tiger sharks usually
occupy deeper water, making vertical migrations into shallow reef areas at night to feed. However, larger specimens may make midday excursions into
inshore areas on overcast, rainy days (when light levels are low), or if they are injured or sick. Juveniles and adolescents are more regular
inhabitants of shallow water during the day, at least in certain areas. It has been suggested that smaller specimens occupy a different habitat
than adults to avoid being eaten. But overall, fishing data suggests the social structure of this species is ill-defined, with males and females
displaying none or little segregation by size or sex and with no distinct nursery areas. They do not school, but may aggregate around a large food
source, like a whale carcass. They are usually solitary, but are sometimes observed in pairs. This species is known to migrate to warmer waters
during summer months.
Distinguishing Characteristics:
This species is hard to mistake. It has a large blunt snout, a well developed keel on the caudal peduncle and dark vertical stripes on it's body
(these are less conspicuous or absent on adults).
Diver Interaction:
This is one of the most dangerous sharks, having attacked divers, surfers, swimmers and boats. An underwater encounter with a tiger shark can be
exhilarating, but this shark should be treated with the utmost respect! They have been known to harass divers during shark feeds and are not at all
finicky about what they eat. However, for the daring shark diver, there is nothing more thrilling than an open water encounter! The tiger shark is
most often encountered by divers in Florida and the Bahamas, the Coral Sea, New Guinea, some areas in the Philippines, and the Hawaiian Islands.
Best Places to See:
Florida and Bahamas; Oahu, Hawaiian Islands; Lizard Island and Raine Islands, Great Barrier Reef.
