Tiger Shark

The tiger shark is a requiem shark whose name comes from the dark gray stripes and spots running along its body vertically. These markings are more readily observable in younger sharks, fading away with age.

Among the largest extant sharks, the tiger shark is only behind the whale, basking, and great white sharks in terms of size. It is even regarded as the second-largest predatory shark after the great white. With the great white and bull sharks, the tiger shark is a member of the “Big Three”, as they are most well known for attacking humans. Tiger sharks have a more sleeker build than the great white shark which is bulkier. When it comes to the difference between the tiger, and bull shark, the latter shows increased aggression than the former.

Description

Size: Length: 10 ft 8 in–13 ft 11 in (3.25–4.25 m) Weight: 386 to 1,400 lb (175 to 635 kg)

Teeth: The teeth are serrated, with sideways-pointing tips. Like most sharks, their teeth are continually replaced by newer ones throughout their lives.

Fins: It has a set of long, pectoral fins, as well as a pelvic and anal fin. There are two dorsal fins, a larger one on its back and a smaller one lower down. The caudal fin on its tail is very large and helps it pivot quickly.

Body and Coloration: It has a broad, flat head, shaped like a wedge, with a snout shorter than the width of the mouth, long labial furrows, and a slender body. The skin of a tiger shark comes in shades of blue or light green, while their underbelly is white or light yellow. Dark spots and stripes, which give the shark its name, are primarily visible in juveniles, fading as it matures.

Range and Distribution

They are seen along the Gulf of Mexico, beaches of North American, and certain parts of South America. Tiger sharks are also commonly observed in the Caribbean Sea. Other locations include Africa, Australia, China, India, and Indonesia.

Habitat

The tiger shark resides close to the coast, mainly in tropical and subtropical waters worldwide. Its behavior is primarily nomadic, guided by warmer currents. During the cold months, it stays closer to the equatorial regions, which are warmer. It mostly remains in deep waters (up to 140 m) surrounding the reefs, but it does move into channels to pursue prey in shallower waters, though that is quite uncommon indeed. In fact, as per studies they are not found below a depth of 350 m, though in rare cases these sharks dwell in waters that are about 900 m deep. They prefer turbid coastal areas where freshwater runoff occurs as different prey species group together in these areas.

Diet

This shark is an apex predator with a vast appetite, aggressively consuming various marine prey. Their diet includes aquatic birds and mammals, bony fish, crabs, lobsters, porpoises, shellfish, skates, small sharks, snakes, squid, rays, and turtles. Even some terrestrial mammals like brown rats, cats, dogs, goats, horses, and sheep become part of their diet from time to time.

Lifespan

Tiger sharks live for 12 years on average.

Behavior

• They are nocturnal and mostly solitary, only coming together during feeding and mating periods.
• Feeding is a communal activity with a social hierarchy. The larger sharks feed first, and once they are done, the smaller sharks begin to eat. This activity is relatively peaceful, with instances of violence amongst the feeding sharks being very low.
• These sharks are nocturnal hunters, feeding in the shallow waters at night, and coming back to the deep waters during day time.
• Despite their overall lethargic demeanor, they are strong swimmers, capable of reaching speeds of 20 mph. Once the intended prey is in range, a quick burst in their direction allows it to capture its target before it has the chance to escape.

Do They Attack Humans

While the number of bites by these sharks is one of the largest, second only to the Great White Shark, the actual biting rate is low and tends not to be fatal most of the time.

Predators

As apex predators, tiger sharks have few natural predators. However, there are records of killer whales working in a group to bring down tiger sharks. The juveniles are often eaten by the adults of their own species, and other shark species too.

Adaptations

• Tiger sharks have small pits on their snouts, holding electroreceptors or sensing organs, known as the ampullae of Lorenzini, enabling them to detect electric fields. This lets them sense the weak electrical impulses generated by prey, allowing them to hunt.
• The spots and stripes on their skin act as effective camouflage underwater due to their countershading.
• Like most fish, tiger sharks have a lateral line that acts as a “sixth sense”, detecting minor vibrations in the water.
• Tiger sharks have good eyesight with a reflective layer behind their retina, the tapetum lucidum, enhancing vision in low-light conditions. A clear membrane covers their eyes like a see-through eyelid.

Mating and Reproduction

Tiger sharks mate via internal fertilization, giving live birth to 10-80 pups in a single litter. The male inserts his claspers into his mate’s cloaca (genital opening). Throughout the mating process the males firmly hold on to the females using their teeth to keep them in place, causing immense discomfort to their mates. The tiger sharks do not connect to their young via the placenta; instead, embryos develop inside individual eggs until they hatch.

Life Cycle

The baby tiger sharks develop inside the mother’s body for up to 16 months. A newborn shark is usually 20 to 30 inches long. Males become sexually mature at 7.5 to 9.5 ft, while females do so when they are 8.2 to 11.5 ft long. Females mate once every three years.

Conservation Status

According to the IUCN, the tiger shark is “Near Threatened” or “NT”. This is due to the high rate of finning and fishing. In 2010, Greenpeace International identified it as a fish which had a high chance of being obtained from unsustainable fisheries, and put it on the seafood red list. Meanwhile, the New Zealand Department of Conservation classified this shark as “Migrant” with “Secure Overseas” under the New Zealand Threat Classification System in June 2018.

Interesting Facts

• As these sharks are known for eating almost anything, several non-food items have been found in their stomachs. These include baseballs, bottles, cans, coal, license plates, nails, oil cans, rags, tires, and even a chicken coop!!!
• The tiger shark is considered na ʻaumakua, i.e., spirits of their ancestors by some Hawaiians, who believe that their eyeballs have special powers of visual perception.
• On November 2018, marine biologist Kori Garza and her team encountered an 18 ft. long tiger shark, whom they christened Kamakai. She noted as a result of its big size, the shark’s mouth was constantly open.
• In 2003, Bethany Hamilton, at that time 13 years old, was lying on her surfboard when a tiger shark bit off her left arm. She survived and would go on to have a stellar surfing career, and the shark that bit her was later identified.