Day Octopus

Photo: Doug Finney · CC BY-NC

While divers focus on the aerial manta display, day octopuses emerge from reef crevices on the surrounding sand flat at night to hunt crabs and bivalves, their chromatophore ripples creating a secondary light show visible to divers with torches. They are among the most cognitively complex invertebrates on the reef and have been observed using rocks as doors to seal their dens — behaviour that suggests deliberate spatial planning.