Sharks typically have a streamlined, fusiform (rounded and tapered) body shape that helps reduce drag while swimming. They have tough skin covered with toothlike scales called dermal denticles. Their coloration often includes a gray dorsal side and a lighter, sometimes white, ventral side, which helps with camouflage in the water. Key features of sharks include:
- A pointed snout
- Sharp, triangular teeth that are often serrated
- Five to seven gill slits on each side
- Two dorsal fins (except for some species like the frill shark which has one)
- Pectoral fins that are not fused to the head
- An asymmetrical, muscular, upturned tail fin (heterocercal tail) where the upper lobe is typically larger than the lower lobe
- Eyes that can be larger proportionally than other fish, with some species like the great white having deep blue irises
- They lack a swim bladder and must swim continuously to avoid sinking
Shark sizes range widely, from the small dwarf lanternshark at about 17 cm (7 inches) to the massive whale shark that can reach up to 12-15 meters (40-50 feet). Color patterns vary; some sharks have spots, stripes, or bands for camouflage and species identification. Different species show some variation in appearance. For example:
- Great white sharks have a conical snout and countershading coloration (greyish dorsal and white ventral side)
- Whale sharks are marked with a unique checkerboard pattern of spots and stripes
- Frill sharks have eel-like elongated bodies with a single dorsal fin
Overall, sharks have a tough, functional body designed for efficient swimming, hunting, and camouflage in aquatic environments.
