Squaliformes – Dogfish sharks
Unexplored compact treasures in the depths of the ocean, also known as Spiny dogfish
Squaliformes is a large and diverse order of sharks with unique characteristics: they have five to seven pairs of uncovered gill slits, spiracles, two dorsal fins (often with a spine on the front one), and they lack an anal fin. Many of them can generate light, making them bioluminescent to some extent. Their skin is densely covered in denticles; it’s like having a fashionable suit of armour that helps them swim faster and stay protected! Their body is elongated and lean, tapering towards the tail.
They like to stay close to the bottom of the ocean (deep sea), but some also enjoy taking nighttime trips up and down the water. They’re found in different parts of the world, from cool temperate areas to warm tropical waters. You can even spot them in the freezing Antarctic and the icy Arctic regions.
They give birth to live young instead of laying eggs. Many squaliformes are often targeted for commercial purposes, either for their meat as food or for pharmaceuticals. Their commercial harvesting poses a threat to their survival and requires conservation attention.
Squaliformes have clever ways of nourishing their babies inside the mother’s body. They use either yolk sac viviparity or mucoid histotrophy. The yolk sac provides essential nutrients like a ready-made meal, while mucoid histotrophy adds extra nourishment through a slimy substance the mother produces. It ensures the babies have enough food to grow and develop until they are ready to be born.