Atlantic Bobtail Squid

• It houses bioluminescent bacteria of the genus Vibrio in a light organ, with which it can match the moonlight coming from above and erase its own shadow from the predators below.
• Each generation of bobtail squid is born free of bacteria and must capture its symbiotic bacteria from the seawater.
• It is tiny, just a few centimetres long, and its rounded body with two lateral fins gives it a look quite unlike that of a common cuttlefish.
• By day it buries itself in the sand, digging with jets of water, and lies covered with only its eyes showing.
• Like its Hawaiian relative, it hosts symbiotic luminous bacteria in an organ of the mantle, which it uses for counter-illumination, erasing its silhouette from predators below.
• It lacks the calcified internal shell of a cuttlefish: its cuttlebone is reduced or absent, a trait of the group.
• It lives barely a year and dies after breeding, like almost all small cephalopods.
• It is common along Europe's Atlantic coasts but goes completely unnoticed because of its size and its nocturnal habits.

Skeleton type

Invertebrate - no rigid skeleton (mollusc)

Habitat and environment

Shallow sandy bottoms of the north-eastern Atlantic, from 0 to 100 m

Sources consulted: Marine Life Information Network; Jereb y Roper, FAO Cephalopods of the World; Lista Roja de la UICN