Practically no predator has such a bad reputation as the shark. Their reputation is terrifying, though they are at home at sea, so encounters with people are limited. Every predator has a life outside of hunting and feeding. But in the short periods of time that people are able to observe them in the wild, it is almost impossible to get a true idea of their daily lives.
Habitat preferences are mainly determined by water temperature and depth, so sharks living in cold, temperate and tropical seas remain separate groups.
In the warm waters surrounding French Polynesia in the South Pacific Ocean, many different species of tropical sharks can be found. Whitetip reef sharks are usually found near islands. They rest most of the day. Unlike other shark species, which must be in constant motion for water to pass through their gills, enabling them to breathe, white reef sharks are able to pump water into their gills while resting on the sea floor. It is the distinctive white tips on its hind flippers that give it its name. They are waiting here until it gets dark and it’s time to hunt.
Black tip reef sharks are often seen around coral reefs in the South Pacific Ocean. Divers should not worry that they are there in large numbers often. Like many species of sharks, they are very curious and often approach humans underwater. But due to its relatively small size, it does not pose a danger to humans. Its beautifully ornate dorsal fin often protrudes across the surface of the water.
Lemon sharks are among the most impressive of all sharks. Their name comes from their distinctive greenish-yellow colour. It can grow to an impressive length of over three metres. In a manner typical of sharks, lemon sharks are equipped with rows of teeth that can be replaced multiple times. Some sharks lose 30,000 or more teeth during their lifetime. The distinctive second dorsal fin is conspicuously large. They are believed to be more nervous than other types of sharks, so for divers it is advised to keep their distance.
The gray reef shark is among the most common species of shark that live around coral reefs. These sharks are often found in impressive numbers near the channels that cut through the atoll. The currents that push through the passages in the corals allow them to let the water flow through their gills using as little energy as possible. The gray reef shark is usually less than 2 meters long, making it one of the smallest species of shark. Their diet consists of small reef fish and crustaceans. Gray reef sharks have formidable enemies. All larger species of sharks and even the silver tip have been known to feed on them.
Silvertip sharks can be easily distinguished by the light colored tips of their fins. They grow larger than gray reef sharks and hunt farther from the reefs and also at greater depths. The Blue Racers stay in their vicinity, but why they stay is still a mystery.
Oceanic whitetip sharks are rarely found near the coast. They are easily recognizable by their high, strongly rounded dorsal fins. These sharks are usually solitary and belong to the few species that can be very dangerous to humans. But the adults rarely encounter people, as only the young keep within easy reach of the coast. Guide fish are often found accompanying these sharks. They probably stay to feed on dead skin, parasites, and bits of leftover food, and sharks tolerate their pursuers.
Next to the great white shark, tiger sharks are the most dangerous sharks. They are named for their distinctive pattern of dark stripes. It can reach a staggering over five meters in length. Its size alone is worthy of respect. Since tiger sharks can be really curious, they don’t shy away from humans. They eat almost anything, including other sharks, seabirds, crustaceans, and even carrion, and a wide variety of waste has been found in the stomachs of tiger sharks.
Great hammerhead shark – also known as the king of sharks. He is shy and rarely gets close to people. For scientists, the mighty hammerhead still raises all sorts of mysteries. Her odd head shape means she has some pretty impressive abilities. Some scientists suspect aerodynamic reasons for this. The wide profile can provide better stability during fast maneuvers. It has also been observed that they pin rays to the ground with their heads before devouring them. But it is also possible that the head could better record the electrical signals emitted by the sharks’ prey. Others believe that these sharks are able to smell in three dimensions.
Each type of shark has its own set of behaviors. But even within each species, there are very individual differences between animals. There are those who remain wary, and there are individuals who are curious, brave and ruthless. Despite the fear that sharks tend to arouse in humans, they are the ones who are most threatened. Millions are killed every year as a delicacy, whether for fun or by accident, when they are caught in huge fishing nets. But if sharks go extinct, it will have far-reaching consequences for ocean ecosystems around the world.