Zebra Shark

The zebra shark, scientifically known as Stegostoma tigrinum, is the only member of the family Stegostomatidae and is categorized as a species of carpet shark. It inhabits the tropical Indo-Pacific region and can be found in coral reefs and sandy flats up to a depth of 62 m (203 ft). Adult zebra sharks are easily recognizable due to their five longitudinal ridges on a cylindrical body, a low caudal fin that accounts for around half of their total length, and a pattern of dark spots on a pale background. In contrast, young zebra sharks under 50-90 cm (20-35 in) in length have a different pattern consisting of light vertical stripes on a brown background and do not possess the distinctive ridges. These sharks can grow up to 2.5 m (8.2 ft) in length.

Zebra sharks are nocturnal creatures that spend most of their days resting motionless on the seafloor. During the night, they actively search for molluscs, crustaceans, small bony fishes, and possibly sea snakes within holes and crevices in the reefs. While they are typically solitary throughout most of the year, they occasionally form large seasonal aggregations. Female zebra sharks are oviparous, producing several dozen large egg capsules that they anchor to underwater structures using adhesive tendrils.

The zebra shark has a distinctive physical appearance with a cylindrical body, a large slightly flattened head, and a short blunt snout. Small eyes are positioned on the sides of the head, while the spiracles, also relatively large, are located behind them. The last three of the shark's five short gill slits are positioned over the bases of its pectoral fins, with the fourth and fifth slits being closer together than the others. Each nostril possesses a short barbel and a groove that extends from it to the mouth. The mouth is almost straight and features three lobes on the lower lip as well as furrows at the corners. The upper jaw contains 28-33 tooth rows, while the lower jaw has 22-32 tooth rows. Each tooth consists of a large central cusp flanked by two smaller ones. Adults have five distinct ridges along their bodies, one along the dorsal midline and two on each side. The dorsal midline ridge merges into the first dorsal fin, which is placed halfway along the body and twice the size of the second dorsal fin. The pectoral fins are broad and large, while the pelvic and anal fins are smaller but bigger than the second dorsal fin. The caudal fin is nearly as long as the rest of the body, and it has a minimal lower lobe and a pronounced ventral notch near the tip of the upper lobe. The zebra shark typically reaches a length of 2.5 m (8.2 ft), with an unconfirmed record of 3.5 m (11 ft). There is no significant difference in size between males and females.

Young zebra sharks display a dark brown color on their upper body and light yellow on their lower body, along with yellow vertical stripes and spots. As they grow to a length of 50-90 cm (20-35 in), the dark areas begin to break up, transforming the overall pattern from light-on-dark stripes to dark-on-light spots. Among adults, there is considerable variation in patterns, enabling individuals to be identified.

The zebra shark is abundant in the tropical waters of the Indo-Pacific region, ranging from 🇿🇦 South Africa to the 🌊 Red Sea and the Persian Gulf, including locations such as 🇲🇬 Madagascar and the 🇲🇻 Maldives, 🇮🇳 India and Southeast Asia, including 🇮🇩 Indonesia, the 🇵🇭 Philippines, and Palau, as well as northward to 🇹🇼 Taiwan and 🇯🇵 Japan, eastward to 🇳🇨 New Caledonia (🇫🇷 Overseas France) and 🇹🇴 Tonga, and southward to northern 🇦🇺 Australia. These sharks typically inhabit the continental and insular shelves and can be found from the intertidal zone to a depth of 62 m (203 ft). Adults and large juveniles are often found in coral reefs, rubble, and sandy areas. Zebra sharks occasionally cross oceanic waters to reach isolated seamounts, with individual sharks recorded to have traveled up to 140 km (87 mi). Their daytime behavior consists mainly of resting on the seafloor, propping up the front of their bodies with their pectoral fins, and positioning themselves facing into the current with their mouths slightly open to aid respiration. They become more active at night or when food is available, displaying an ability to swim skillfully and with agility by undulating their bodies and tail in an anguilliform (eel-like) manner. They have been observed remaining stationary in a steady current by using sinuous waves of their tails.

The zebra shark primarily feeds on shelled molluscs, although it also consumes crustaceans, small bony fishes, and potentially sea snakes. Their slender and flexible bodies allow them to enter narrow holes and crevices in search of food, aided by their small mouths and well-developed buccal cavities, enabling them to create a powerful suction force when extracting prey. Larger fishes, notably other sharks, and marine mammals are potential predators of zebra sharks. This shark is known to be parasitized by four species of tapeworms belonging to the Pedibothrium genus.

While zebra sharks are docile and slow-moving, they are not considered dangerous to humans and can be approached underwater with ease. However, there have been instances of zebra sharks biting divers who pull on their tails or attempt to ride them. According to the International Shark Attack File, only one unprovoked attack has been recorded, with no resulting injuries. Zebra sharks attract ecotourist divers in various locations, such as the 🌊 Red Sea, the 🇲🇻 Maldives, 🇹🇭 Thailand's Phuket and Phi Phi islands, the Great Barrier Reef, and other sites. Many of these sharks have become accustomed to the presence of humans and are comfortable taking food from divers' hands and allowing themselves to be touched.