Britannica
Sources used in this answer
How do cephalopods use the mantle and funnel for jet propulsion?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
cephalopod
Blue-ringed octopus (genus Hapalochlaena).
Cephalopods utilize their highly muscular mantle and a flexible funnel to achieve jet propulsion, a primary method of locomotion for the group.1
The process functions through a cycle of expansion and contraction:
- Intake: The mantle relaxes, causing it to expand and draw water into the mantle cavity. In many species, this water enters around the neck region or the mantle aperture.1
- Expulsion: When the mantle contracts, the aperture closes via locking mechanisms and muscle contraction. This forces the trapped water out through the funnel.1
- Steering: The funnel acts as a jet nozzle that can be directed in various ways, providing the animal with significant flexibility for steering and executing quick movements.1
In more efficient systems, such as those found in oceanic squids, a nonreturn valve prevents water from entering the funnel incorrectly during the intake phase. While this mechanism allows for rapid movement, it is distinct from the slower swimming or hovering achieved by fins in some species.1