The snapping shrimp and Goby fish share a burrow in the sea bed.

When the entrance of their burrow gets littered with ruble, the shrimp clears the rubble using its claws as

a mechanical digger.

When the shrimp is thus busy, the Goby fish stands guard with one of its antennae touching the shrimp.

When the Goby fish senses any danger, it wriggles its body. The shrimp is alerted by the movement of it

antennae. It darts to the safety of it burrow- closely followed by the Goby fish.