Tiger shark (Galeocerdo cuvier) is the only species of the genus tiger sharks (Galeocerdo). The species was first described by Peron and Lessueur in 1822, under the name Squalus cuvier. In 1825 Blainville has included this species to the genus Carcharhinus, Carcharhinus lamia calling it. Müller (Muller) and Henle in 1837 tiger shark was transferred into a separate genus Galeocerdo and gave her the specific name of Galeocerdo tigrinus. Gill in 1962 called the described type of Galeocerdo tigrinus. Currently, the tiger shark is the scientific name Galeocerdo cuvier, on the grounds that this species gave the name of her who first described it Lessueur, however, the generic name had to change, as the tiger shark belongs to the genus Squalus (spiny sharks), as suggested Lessueur, and is a separate a monotypic genus, as noted above.
Class: Chondrichthyes (cartilaginous fish)
Subclass: Elasmobranchii (platinotipiya, or elasmobranchs)
Superorder: Selachimorpha or Selachii (sharks)
Order: Carcharhiniformes (carcharhiniformes)
Family: Carcharhinidae (carcharinidae)
Genus: Galeocerdo (tiger sharks)
Species: Galeocerdo cuvier (tiger shark)
The upper torso tiger shark has dark stripes and Patana gray-blue or greenish overall background, making the shark got its popular name. Lower torso painted in off-white color. Young individuals have a much more intense and rich color.
Tiger sharks snout is broad and blunt. A nictitating membrane is very well developed. A spiracle (remnant of the Gill slits behind the eye) is relatively small. Labial furrows very long; the upper groove passes from the angle of the angle of the mouth to the level of the anterior angle of the orbit and is equal to distance from end of snout to eye; lower two times shorter. Pravoslavie fossa is very well expressed. Gill arches – 5 pairs.
Teeth tiger shark teeth well distinguishable from other sharks. They are large, acute, coarsely serrated edges. The outer edge of the tooth deeply concave. The width of the tooth exceeds its length. Operate one or two series of teeth. Such structure of the teeth allow the shark to literally cut the flesh and bones of their victims. In addition, tiger sharks have some of the strongest jaws among the sharks and fish in General, which allows them to easily crush the shells of sea turtles.
Despite of the slowness and somewhat bulky build, the tiger shark is one of the best swimmers among carcharhinoid sharks, although usually swims very slowly.
Dimensions and weight
The tiger shark is one of the largest actively hunting predatory sharks, second in length only to the white shark (Carcharodon charcharias), atlanticheskoi, or Greenland (Somniosus microcephalus) and Pacific (Somniosus pacificus) sharks and polar gray zhestyanoi shark (Hexanchus griseus). However, the body size of sharks above often overlap. Females are larger than males.
I must say that the exact maximum sizes of sharks, especially so large, it is difficult to determine because data from different sources vary in addition from time to time there are reports of very large specimens, many of which are untested. According to V. P. Gubanov, V. V. Kondyrina and N. A. Myagkova maximum body length of a tiger shark – 5.5 meters (Gubanov, Kondyurin, Myagkov, 1986). Ritter (Ritter, 1999b) also specifies the maximum length of this species is 5.5 metres for females and 4.5 metres for males. Other sources give a maximum estimate of the length of the tiger shark in as much as 6 meters (Froese & Pauly).
The average length of tiger sharks does not exceed 4.5 m and varies from approximately 3 to 4.2 metres, and the weight of the body is approximately from 385 to 635 kg (Knickle).
Tiger shark eats virtually all it can handle and catch. Its menu includes numerous dolphins (butylone, dolphins, etc.), sea lions and seals, dugongs, sea turtles and snakes, crustaceans, all kinds of shellfish and sea birds, and of course various fish, including other smaller species of sharks, including smaller sharks of their own species. Sometimes tiger sharks attack on the sick or even young gray whales. In addition to live prey, they also eat carrion (carcasses of the same gray whales and other animals).
The tiger shark is notorious for its cannibalism and among the most dangerous to humans shark species occupies a leading place.
The tiger shark belongs to the viviparous shark species. Sexual maturity tiger sharks reach with the body length of 2.1-2.4 meters (Gubanov, Kondyurin, Myagkov, 1986). According to other reports, males reach sexual maturity at a length of 2.3 to 2.9 metres, and females at 2.5 to 3.5 meters (Hamilton, Bethany, 2003). Females usually breed every three years (Ritter, 1999b).
Fertilization in domestic tiger sharks, which is characteristic of all elasmobranch (Elasmobranchii). During mating, the male inserts into the female cloaca of one of his peregorodiev.
Incubation of young lasts until approximately 16 months (Knickle). The number of fry can reach 30-50 individuals, but usually 12-18 (Gubanov, Kondyurin, Myagkov, 1986). According to other sources – from 10 to 80 (Knickle). The length of newborn sharks is about a meter (Gubanov, Kondyurin, Myagkov, 1986). According to other sources – about 51 to 76 cm (Knickle).
Distribution and habitat
Tiger sharks are cosmopolitan and are found in virtually all seas and oceans of tropical, subtropical and temperate areas, in surface water, at depth up to 120 meters (usually less). These sharks can be found in the pelagic zone, however, they prefer coastal waters (one of the reasons for the relatively frequent attacks on people).