# Bivalve Shell Utilization by Juvenile Octopus vulgaris in Sandy Substrates

## TL;DR

Juvenile common octopuses use empty bivalve shells for protection in sandy environments, adapting to high predation risks by camouflaging and strategically positioning themselves.

## Contribution

This study documents the novel use of bivalve shells by juvenile octopuses in sandy habitats as an adaptive behavior to predation.

## Key findings

- Juvenile octopuses prefer shells that fit their body size for protection and reduced exposure.
- They use camouflage and strategic positioning within shells to avoid predators.
- Some octopuses use bipedal locomotion when threatened to escape quickly.

## Abstract

The early life stages of
Octopus vulgaris
face significant challenges in sandy environments, where shelter is limited and predation risk is high. This study examines how juvenile octopuses adapt to these conditions, focusing on their use of empty bivalve shells as shelters. Between May 2022 and June 2023, through four SCUBA diving expeditions in the Cíes Islands, NW Spain, nine juvenile octopuses were found inhabiting bivalve shells. The juveniles preferentially selected shells that fit their body size, providing protection and minimizing exposure. They manipulated the shells for security and positioned themselves strategically for optimal visual surveillance. Additionally, they used camouflage techniques, blending with the sandy substrate. When threatened, some octopuses displayed bipedal locomotion to enhance their escape. This study highlights the adaptive flexibility of juvenile
O. vulgaris
in response to predation pressures in sandy habitats, adding to the growing but limited knowledge of habitat‐specific behaviors that can help contribute to the conservation strategies of wild populations.

This study investigates how juvenile
Octopus vulgaris
adapt to sandy environments with limited shelter and high predation risk by using empty bivalve shells for protection. Through four SCUBA expeditions in NW Spain, nine juveniles were observed using shells that fit their body size, strategically positioning themselves for surveillance and employing camouflage. These behaviors emphasize the species' adaptability and have important implications for conservation in sandy habitats.