Some marine animals live together in mutually beneficial relationships.

One well-known example is the partnership between the snapping shrimp and the goby.
The snapping shrimp digs and maintains the burrow, while the goby stands guard outside.
Because the shrimp has poor eyesight, it relies on the goby to warn of approaching danger.
When a threat appears, the goby signals the shrimp with body movements, and both quickly retreat into the burrow.

Cooperation increases survival