1. CounterShading: Dogfish sharks exhibit counter-shading, a form of camouflage where the dorsal (upper) surface of their bodies is darker, while the ventral (under) surface is lighter. This coloration helps them blend with their surroundings, making it difficult for predators above and below to spot them.
2. Dermal Denticles: Their skin is covered in small, tooth-like dermal denticles, giving it a rough texture. These denticles serve multiple purposes, including providing protection from predators and parasites and enhancing their hydrodynamic efficiency by reducing drag in water.
3. Gill Slits: Dogfish sharks have five pairs of gill slits on either side of their heads. These slits facilitate efficient respiration, allowing water to flow over the gills and extract oxygen.
4. Spiracles: Located above their eyes are a pair of small openings called spiracles. These spiracles allow dogfish sharks to draw in water and expel it through their gills, even when their mouths are closed. This feature is especially useful when they are scavenging on the seafloor.
5. Teeth: Dogfish sharks have multiple rows of sharp, triangular teeth, which are continuously growing and replaced. Their teeth are effective at grasping and tearing prey, such as fish, squid, and crustaceans, which form the majority of their diet.
6. Liver: Dogfish sharks possess a large liver that contains low-density oils, providing buoyancy and allowing them to maintain neutral buoyancy in the water. This adaptation helps them save energy while swimming.
7. Claspers: Male dogfish sharks have claspers, which are modified pelvic fins used during reproduction. Claspers help attach the males to females during mating, ensuring successful sperm transfer.
8. Ampullae of Lorenzini: These specialized electroreceptors are scattered across their heads, enabling dogfish sharks to detect electrical fields generated by their prey and other animals. This sensory ability aids in finding food and navigating in their surroundings.
9. Lateral Line System: Dogfish sharks, like many other fish, possess a lateral line system. This series of sensory cells runs along the sides of their bodies and helps them detect water movement, vibrations, and pressure changes, providing information about their environment and potential threats.
10. Viviparity: Dogfish sharks are viviparous, meaning they give birth to live young rather than laying eggs. Embryos develop inside the female's body until they are ready to hatch. This reproductive strategy offers protection to developing offspring until they are relatively well-developed and have a better chance of survival.