|Length||Up to 17 ft (5 m)|
|Weight||1900 lbs (860 kg)|
|Conservation Status||Near threatened|
|Preferred Habitat||Tropical and Temperate Oceans|
|Average Litter Size||30-35|
|Main Prey Species||Schooling fish, squid, cuttlefish, crustaceans, sea birds|
|Predators||Larger sharks, orca|
The tiger shark is the only member of the genus Galeocerdo and is a large, predatory species. Tiger sharks are found in many temperate and tropical oceans and are known for their distinctive stripes and spots on their flanks, which resemble a tiger’s stripes. They are among the largest extant shark species, ranking behind only the whale shark, basking shark, and great white shark in average size.
Tiger sharks grow to a total length of 17 ft (5 m) and weigh over 1 900 lb (860 kg). They are robust but streamlined and have two triangular dorsal fins and large pectoral fins. Along with all other members of the order Carcharhiniformes, it also has an anal fin and five gill slits, along with a nictitating membrane over its eyes. The species is dimorphic, with females being larger than males by 3 ft (1 m) or more. Their skin ranges in color from blue-grey to light green with darker charcoal stripes on their sides and white undersides, reminiscent of the Great White Shark. The stripes of tiger sharks are usually more prominent on juvenile sharks than on adults.
Distribution and Range
Tiger sharks are pelagic animals, meaning they swim freely in the water column as opposed to living on the bottom. They can be found throughout most of the world’s tropical and temperate oceans, although prefer to stick to the warmer end of the temperature spectrum. Individuals are often nomadic, following warmer-water currents around the sea in the summer and remaining close to the equator during the winter. They inhabit deep water, generally around 420 ft (140 m) but often much deeper. They are also occasionally observed in shallow coastal waters and are commonly seen in Hawaii, the Caribbean, and Florida, for example.
Predators and Prey
They are largely solitary and hunt primarily at night, approaching reefs in search of various food items. They may follow schools of fish into shallow inshore waters or attack a turtle it may come across while traveling the sea. Tiger sharks are also known to eat various crustacean species as well as seals, birds, squid, sea snakes, and even dolphins. They will even eat other sharks, generally smaller species or juveniles of larger species.
Tiger sharks have few natural predators but are sometimes taken by groups of orcas that will use their size advantage and complex social structure to overtake the shark. In addition, they are the victim of illegal fishing practices such as finning. Due mostly to this and the destruction of natural marine habitats around the world due to pollution and destructive fishing techniques, the tiger shark is listed as “Near Threatened” on the IUCN Red List of Threatened Species.
Male tiger sharks reach sexual maturity when they reach about 9.5 ft (3 m) in length while females, who grow bigger than males in general, reach sexual maturity at about 11.5 ft (3.5 m). Although individual females will reproduce just once each three years, tiger shark breeding season occurs each spring, between March and May in the Northern Hemisphere and between November and December in the Southern Hemisphere. Breeding occurs by means of internal fertilization. While mating, males may hold the female with its teeth, often causing her injury in the process.
Following copulation, the female will host up to 100 fertilized embryos. Unique with the Carcharinidae family, tiger shark embryos hatch and develop internally, being carried by the mother for up to sixteen months. At this point she will give birth to about thirty-five live, well-developed offspring up to 30 in (76 cm) in length. The lifespan of tiger sharks is still unclear, however, they are known to be capable of living for at least 12 years.
Are They Dangerous?
Only one other species of shark – the Great White Shark – has killed more humans than tiger sharks. That being said, humans are not a natural prey item of tiger sharks. Like most fatal shark attacks, encounters with tiger sharks are normally the result of the shark taking an interest in the person, and attempting a ‘test bite’ to determine what it is. Most sharks lose interest and swim away, but unfortunately, the resulting injuries can be fatal. Because tiger sharks are generalist hunters and will attempt to eat almost anything, they do injure or kill humans more than many other shark species. However, considering the number of potential human-shark interactions in the world each year, very few result in an attack and even fewer are fatal.
Fun Facts about the Tiger Shark!
From their heightened predatory senses to their massive size, tiger sharks are one of the most infamous shark species in the world. It’s not without unique and advantageous adaptations that it came to be such a dominant predatory force throughout the oceans of the world.
Tiger sharks, like many other shark species, have some unique adaptations that allow them to be the great predators they are. First, they are able to detect the small electric fields generated by their potential prey. They do this using electroreceptors known as ampullae of Lorenzini, which sit in pits on the shark’s snout.
In addition to the ampullae of Lorenzini, sharks also have an additional unique sensory organ known as a lateral line. This extends down their sides over most of the length of their body. It is filled with a substance called endolymph, the same fluid that is found in the inner ear of humans and is vital in allowing us to remain balanced. In sharks, this lateral line is integrated with the nervous system, and effectively allows them to find prey by detecting minute vibrations in the water.
A True Generalist
The tiger shark is known for having one of the most wide-ranging pallets of all shark species. In fact, they are so interested in trying everything that they also end up consuming a variety of inedible objects, largely man-made. Unfortunately, with the oceans becoming more and more polluted with anthropogenic waste, this is not a beneficial trait for the species. Along with its sheer overall size, this feeding habit of the species may also be why it is known by many as a dangerous species, as it will often show interest in anything that has the potential to be food.
A Special Weapon
Tiger sharks have unique teeth. Each tooth is serrated, culminating in sideways pointing tips, generally to the left on the left side of the mouth and to the right on the right side of the mouth. Likely a reflection of the tiger shark’s diet, the teeth are shorter than other sharks of comparable size such as the great white shark. However, they are very sharp, and the serrations give them the cutting ability to bite through their prey more quickly than would otherwise be possible. This is necessary for some of the tough prey items the tiger shark will attack, such as sea turtles with their large shells.
Predictably, tiger shark teeth are often damaged or broken by such prey items. However, this does not cause a problem for the shark often dubbed ‘the man-eater’, as its teeth are continuously replaced by new rows of teeth throughout the greet predator’s lifetime.