Why do squid swim backward?

Squids and other cephalopods such as the cuttlefish and octopus do not swim backward. They are indeed unique among marine animals because they use jet propulsion to move about in the water at incredible speeds. Cephalopods have a specialized muscular sac known as the mantle, lined with powerful muscle fibers. By expanding and contracting the mantle, they expel water forcibly through a funnel-shaped opening called the hyponome. This generates a jet of water, propelling the cephalopods forward, while the fins on their body provide stability and directional control.

It's a common misconception that squids and cephalopods swim backward. In reality, their jet propulsion system enables them to execute remarkable movements in the ocean, including forward bursts, hovering, changing direction swiftly, and even backward movement when making subtle adjustments.