The great tiger shark is a unique predator, widely considered one of the most dangerous. Tiger sharks are common in salty waters of the temperate and tropical zones, most of them near the central Pacific islands and in the Indian Ocean.
For a long time, the great white shark was considered the deadliest species. However, some researchers believe that it is the large tiger shark that holds the palm among sea killers.
The size of Galeocerdo cuvier allows it to attack any inhabitants of the ocean, including its relatives.
The average adult length is 6-8 meters, although there are records of sharks caught up to 9 meters long and weighing up to 2 tons.
Origin of the species and description
Photo: Tiger shark
The first ancestors of modern sharks lived on Earth in the Silurian period (420 million years BC). But what kind of fish they were is a debatable question. Cladoselachia are the most studied - they have a body structure similar to sharks, but less perfect, which did not allow them to develop as high a speed.
They evolved from placoderms, shark-like predators - according to one version, marine, according to another, freshwater. Cladoselachia did not leave descendants, but most likely the ancestor of sharks was one of the related and contemporary fish.
Video: Tiger shark
From this it is clear that the early evolution of sharks is very vague and controversial: for example, it was previously believed that their ancestor was Hybodus, a predatory two-meter fish that appeared in the Carboniferous period. But now scientists are inclined to believe that Hybodus was just a side branch of the evolution of sharks.
The situation becomes clearer in the Triassic period, when fish appear that are already clearly classified as sharks. They flourished even then, but a major evolutionary shift occurred with the well-known extinction of the dinosaurs, and with them much of the other fauna.
To survive, the sharks that lived on the planet at that time had to undergo significant restructuring, and they acquired many modern features. It was then that the carchariformes appeared, considered the most advanced of sharks in structure. These include the tiger shark.
The modern species is the only one included in the genus of the same name. The history of the classification is quite complex and confusing - its name in Latin had to be changed more than once or twice. It was described in 1822 by Lesueur and Peron under the name Squalus cuvier.
But just three years later, in the work of Henri Blainville, its position in the classification of species was changed, and at the same time it became known as Carcharhinus lamia. In 1837, it was moved again, highlighting the genus Galeocerdo, the species Galeocerdo tigrinus.
This is where her “travels” ended, but one more change was still made - the right to give a name belongs to the one who first classified it and, although the generic name had to be changed, the original specific name was returned. This is how the modern Galeocerdo cuvier came about.
Scientific classification
- Kingdom: Animalia (animals)
- Phylum: Chordata
- Class: Chondrichthyes (cartilaginous fishes)
- Order: Carcharhiniformes (carcharhiniformes)
- Family: Carcharhinidae (gray sharks)
- Genus: Geleocerdo (tiger sharks)
- Species: Galeocerdo cuvier (tiger shark)
The genus name "Galeocerdo" comes from the ancient Greek "γαλεος" (galeos) = shark and "κερδω" (kerdo) = fox (cunning like a fox).
Appearance and features
Photo: Great tiger shark
The upper part of the body is gray with a bluish tint. Marked by stripes and spots of a darker color - it is because of them that the tiger shark was so named. The lower part is lighter and has a dirty white color. In young individuals the color is richer, the spots are very clearly visible, and as they grow older they gradually “fade”.
It has a wide snout and a small splash, as well as a very large number of teeth, differing in size and sharpness. They are jagged along the edges and are very effective: using them, the shark very easily cuts flesh and even bones. A powerful jaw also helps to do this, thanks to which the shark is able to crush even the shell of a large turtle.
Behind the eyes there are blowholes, through which oxygen goes directly to the shark’s brain. Its skin is very thick and is many times larger than the skin of a bull - to bite through it, you need to have teeth no less large and sharp than those of the tiger shark itself. In a fight with opponents who do not have equally powerful teeth, she can feel like she is wearing armor.
The tiger shark's build appears bulky compared to other species, and its length-to-width ratio makes it look "plump." Moreover, most of the time she swims slowly and not very gracefully. But this impression is deceptive - if necessary, it accelerates sharply, revealing agility and maneuverability.
The tiger shark is one of the largest active hunters and is second in length only to the white shark. However, in comparison with really large sharks, its size is not so large: on average from 3 to 4.5 meters, in rare cases it can grow up to 5-5.5 meters. Weight is approximately 400-700 kilograms. Females reach larger sizes compared to males.
Interesting fact: Sharks' teeth are always so sharp and deadly because they are regularly renewed. In five years, she changes more than ten thousand teeth - a fantastic figure!
sawfish
These cartilaginous fish are a transitional form between sharks and rays. Some experts consider them stingrays, since their gill slits are located not on the sides, but on the ventral flattened side. Their lifestyle, diet, life cycle and behavior, however, are much closer to sharks than to stingrays. We adhere to the latter point of view.
The saw shark's sharp snout is hypertrophied into a long hard outgrowth up to two meters in length, covered on the sides with large sharp teeth - modified placoid scales. The sawfish obtains food in a very original way: it crashes into a school of fish at speed and thrashes its “saw” in all directions, shredding and cutting the prey, which it then calmly swallows. The aggressiveness of the sawfish and its large size - up to nine meters and 2.5 tons - make it very dangerous for humans. It does not attack individual swimmers as often as it attacks boats and surfboards - even fatal cases have been reported.
Where does the tiger shark live?
Photo: Tiger shark fish
They love warm waters, and therefore mainly live in the seas of the tropical and subtropical zones, as well as in the warmest of those that lie in the temperate zone. Most often they swim in coastal waters, although they can also swim into the open ocean. They are even capable of crossing the ocean and sailing to the opposite end, or to the other altogether.
The largest number of tiger sharks can be found in:
- Caribbean Sea;
- Oceania;
- seas washing Australia;
- near Madagascar;
- northern seas of the Indian Ocean.
Their habitat is not limited to this; predators can be found in almost any warm sea. The exception is the Mediterranean, where they are not found, despite suitable conditions. Although they are found in the open ocean, most often during migration, they usually stay close to the coast, mainly because there is more prey there.
In search of prey, they can swim close to the shore and also swim into rivers, but do not move away from the mouth. They usually do not dive to great depths, preferring to remain no more than 20-50 meters from the surface of the water. But they are capable of doing this; they have been seen even at a depth of 1,000 meters.
Interesting fact: They have ampullae of Lorenzini - receptors that respond to electrical signals from vibrations, even very weak ones. These signals are transmitted directly to the sharks' brains. They are detected only from a short distance - up to half a meter, but are more accurate than those coming from the organs of hearing and vision, and allow movements to be calculated with deadly accuracy.
Now you know where the tiger shark lives. Let's now see what this dangerous predator eats.
What does a tiger shark eat?
Photo: Tiger shark
She is completely indiscriminate in food and is able to eat anyone and anything.
The basis of its menu is:
- sea lions and seals;
- turtles;
- crustaceans;
- squid;
- birds;
- octopuses;
- fish, including other sharks, are no strangers to cannibalism.
Her appetite is truly brutal, and she is hungry most of the day. Moreover, even if she has just eaten a hearty meal, if the opportunity arises, she still cannot resist biting something floating nearby, if she has not tried this before.
“Something” - because it applies not only to animals, but also to any garbage. Many strange objects were found in the stomachs of tiger sharks: car tires and fuel cans, deer antlers, bottles, explosives - and many other similar things.
We can say that this is curiosity: a tiger shark is always interested in what a previously unseen object tastes like and whether it is edible at all. If there is no regular food nearby, instead of a long search, tiger sharks attack those who are: for example, dolphins or crocodiles.
They can even attack animals larger than themselves, for example, whales, if they are wounded or sick and cannot resist. Danger threatens not only small whales, but also large ones - for example, in 2006, a case was recorded of an attack on a humpback whale by a whole group near Hawaii.
Their jaws are powerful and wide, which allows them to cope with even such prey. But for the most part, their menu still consists of small organisms. They also eat carrion. The tiger shark is also capable of eating humans - this is one of the most dangerous species, since they can deliberately hunt people.
Danger to people
Photo: Mark Rosenstein
The tiger shark is a formidable predator, second only to the white shark in terms of ferocity and the number of recorded attacks on humans. Tiger sharks are often curious and non-aggressive when encountered, but are one of the three species most often involved in attacks and blamed for human deaths. Although attacks on humans are very rare, they are usually fatal . There are 3-4 attacks annually in the Hawaii area.
Features of character and lifestyle
Photo: Tiger shark in the sea
The tiger shark spends most of its time searching for prey. In this case, it usually moves quite slowly so as not to frighten the victim, but then in an instant it transforms and makes a lightning-fast dash. Thanks to the high dorsal fin and the shape of the snout, it quickly changes direction of movement and is even capable of turning around its axis almost instantly.
If many other aquatic predators have poor eyesight, which they compensate for with an excellent sense of smell, then nature has generously endowed tiger sharks with everything: they have an excellent sense of smell and vision, and in addition they have a lateral line and ampullae of Lorenzini, thanks to which they are able to detect the movement of every muscle prey - this allows you to hunt even in troubled waters.
A shark's sense of smell is so good that a drop of blood is enough to attract its attention from kilometers away. All this makes the tiger shark one of the most effective predators and, if it is already interested in someone, the victim’s chances of salvation become very low.
But the tiger shark also likes to relax - just like tigers, it can lie quietly for hours and bask in the sun, for which it swims to the shallows. Most often this happens in the afternoon, when she is full. It usually goes hunting in the morning and late evening, although it can do this at other times.
Interesting fact: If a tiger shark particularly likes the taste of a particular prey or seems like an easy prey, it will continue to hunt for representatives of the same species. This also applies to people: in 2011, they tried to catch a man-eating shark off the island of Maui for two years. Despite the closure of the beaches, during this time she ate seven people and maimed twelve more.
Save Status
Despite being one of the most common shark species, the International Union for Conservation of Nature lists the tiger shark as Near Threatened throughout its range. However, they are not currently at high risk of extinction.
Fishing pressure, especially on juveniles, has a negative impact on population numbers. Tiger sharks are directly targeted for their fins, meat and oil. Historically, the tiger shark's liver was used to produce oil rich in vitamin A, while its thick, tough skin was used to produce quality leather material. Tiger shark skin has long been used to make traditional Hawaiian drums. In addition to its importance to the fishing industry, the tiger shark remains a highly sought after large fish in the world's recreational fisheries.
Social structure and reproduction
Photo: Great tiger shark
They usually stay alone, but when they meet, they can enter into conflict. This happens if they are angry, or are very different in age and size - then the larger individual may simply decide to eat the smaller one. Sometimes they still gather in groups of 5-20 individuals.
This can happen when there is plenty of food, but such groups are unstable, and conflicts often arise in them. A group of a dozen tiger sharks is capable of killing very large prey, and becomes dangerous even for whales, as well as for other, larger and not so fast sharks. Although they mainly continue to feed on smaller living creatures.
The breeding season occurs every three years. Even the mating ritual of tiger sharks is distinguished by its aggressiveness - they do not betray themselves in this either. In its course, the male must bite the female by the fin and hold her, and this is not a gentle bite at all: wounds often remain on the body of the females. However, sharks still do not feel pain - their body produces substances that block it.
Fertilization is internal. The cubs are gestated for more than a year, after which about 12-16 fry are born, and in some cases up to 40-80. Tiger sharks are ovoviviparous: the cubs hatch from eggs in the stomach, and are born in a developed state.
This is very useful, because the mother will not show any care towards them, and immediately after birth they will have to independently obtain food and defend themselves. The tiger shark does not have a maternal instinct, and it does not eat its own cubs only because before giving birth it loses its appetite, and for some time it remains in this state.
Natural enemies of tiger sharks
Photo: Tiger shark fish
Many large predators pose a danger to young and growing individuals, although most are slower. As the threats grow, there are fewer and fewer threats, and adult fish may have practically no fear of anyone. The most formidable enemies are: swordfish, marlin, spiny-tailed and diamondback rays, other sharks, primarily relatives.
But of all the above, only sharks are the first to attack, and this happens rarely, so tiger sharks have few worthy opponents. But this is if we limit ourselves only to those that can measure their strength with them and enter into direct combat, but there are others that are much more dangerous for this fish.
One of the worst enemies of the tiger shark is the hedgehog fish. It is very small and does not attack itself, but if a tiger shark swallows it, then inside the predator this fish becomes a prickly ball and pierces the shark’s insides, which often leads to its death. Another common cause of shark death is parasites.
People also exterminate a large number of them - perhaps it is at human hands that the bulk of these predators die. In this case, everything is fair: the shark is also not averse to feasting on humans - dozens of attacks occur every year, because tiger sharks tend to swim in crowded places.
Interesting fact: The tiger shark is such a picky eater because its gastric juice is very acidic, allowing it to digest a lot of things. In addition, some time after each meal, she simply regurgitates undigested remains - so sharks usually do not suffer from stomach problems. If you haven't swallowed a hedgehog fish.
