What sensory system helps sharks detect vibrations and movement in water?

The sensory system that helps sharks detect vibrations and movement in water is the lateral line.

A lateral line is a network of sensory organs running along the sides of a fish’s body. In sharks, its main units are neuromasts: tiny structures containing hair cells that respond when water movement bends a jelly-like cupula. This lets the animal sense nearby motion, pressure changes, and vibrations.

The system is especially useful when visibility is poor. A shark can detect the disturbances made by struggling prey, avoid obstacles, and orient toward a moving target even when it cannot see clearly. The lateral line also contributes to spatial awareness and swimming coordination.

It is easy to confuse the lateral line with the ampullae of Lorenzini. Both are important shark senses, but they detect different signals: the lateral line detects mechanical disturbances in water, while the ampullae detect weak electrical fields. A spiracle is an opening used for water intake, and sharks do not have swim bladders.