Among sharks, the great white species has the best olfactory bulb. The shark’s sense of smell is controlled largely by the shark’s brain. A shark can smell a drop of blood a mile away. It then cruises at top towards it. Sharks have their nostrils below the snout.
Sharks actually have roughly the same sensitivity as other fish and can detect smells at between one part per 25 million and one part per 10 billion, depending on the chemical, and the species of shark. At the top end, that’s about one drop of blood in a small swimming pool. Smells reach a shark through the currents, and it would take time for the scent to travel that distance to a shark’s nostrils. The motion of the ocean carries smell molecules with it, so, the more motion, the faster the smell will travel.
Picture Credit : Google