Zebra shark

The zebra shark (Stegostoma tigrinum) is a unique species of carpet shark. It is the only member of the family Stegostomatidae. These sharks live in the warm, tropical waters of the Indo-Pacific region. Their range extends from South Africa to the Red Sea and the Persian Gulf. They are also found in Southeast Asia, Japan, and northern Australia.

Zebra sharks have a very distinct physical structure. They possess a cylindrical body with a large, slightly flattened head. The snout is short and blunt. Five long ridges run along the adult body. One ridge follows the dorsal midline, while two others run along the sides. Their tail, or caudal fin, is exceptionally long. This fin makes up nearly half of the shark's total length.

A fascinating part of their life is how their appearance changes. Juvenile sharks have a pattern of light vertical stripes on a dark brown background. This pattern is why they are called zebra sharks. As they grow toward 3 meters in length, their skin changes. The stripes break up into dark spots on a pale background. Some adults may even show a rare sandy-brown color with dark freckles.

The way these sharks eat is quite specialized. They are nocturnal, meaning they are active during the night. During the day, they rest motionless on the sea floor. They often prefer reef channels to access oxygenated water. At night, they hunt for molluscs, crustaceans, and small bony fishes. Their slender bodies allow them to enter narrow reef crevices. They use a powerful suction force from their mouth to extract prey from holes.

Reproduction for the zebra shark involves a careful process. They are oviparous, which means they lay eggs. Females produce large, dark brown or purple egg capsules. These capsules can measure 30 centimeters long and 15 centimeters wide. The female uses adhesive tendrils to anchor these eggs to underwater structures. She may lay up to 46 eggs over a 112-day period. These eggs are typically deposited in batches of about four.

History shows that scientists once misunderstood these sharks. Early taxonomists thought juveniles and adults were different species. They gave them different scientific names, such as Squalus tigrinus and S. longicaudatus. The species was first described by Seba in 1757. Later, Müller and Henle placed them in the genus Stegostoma in 1837. The name Stegostoma comes from Greek words meaning "covered mouth."

Today, the zebra shark faces significant environmental challenges. The World Conservation Union has assessed the species as Endangered. This is because commercial fisheries catch them for meat, fins, and liver oil. Their numbers are currently dwindling across much of their range. However, they remain popular in public aquaria and for ecotourism diving. Protecting these sharks is vital for the health of coral reef ecosystems.